add k8s version strategy

[rgee0]

Description

Although there is a version strategy for github, whereby the latest version is resolved via the gh release pages something similar did not exist for k8s releases.

https://cdn.dl.k8s.io/release/stable.txt is made available to enable resolution of the latest version.

This change integrates functionality that interrogates this file and uses its contents to assert the version of kubectl to retrieve. This will negate the situation described in #1048 where the version is out of date until the arkade code is updated.

Misc updates to README including the table of tools.

Motivation and Context

• I have raised an issue to propose this change, which has been given a label of design/approved by a maintainer (required)
  Mentioned in a comment on kubectl CLI is outdated by several versions #1048

How Has This Been Tested?

What does kubectl resolve to? Expecting v1.30.0

➜  arkade git:(k8sVersionStrategy) go build
➜  arkade git:(k8sVersionStrategy) ./arkade get kubectl
Downloading: kubectl
2024/05/10 15:18:09 Looking up version for kubectl
2024/05/10 15:18:09 Found: v1.30.0
Downloading: https://dl.k8s.io/release/v1.30.0/bin/darwin/amd64/kubectl
50.15 MiB / 50.15 MiB [---------------------------------------------------------------------------------------------] 100.00%
/var/folders/3w/tv6429v51kl_61rd1fr25sgm0000gq/T/arkade-2175459231/kubectl written.
2024/05/10 15:18:15 Looking up version for kubectl
2024/05/10 15:18:15 Found: v1.30.0
2024/05/10 15:18:15 Copying /var/folders/3w/tv6429v51kl_61rd1fr25sgm0000gq/T/arkade-2175459231/kubectl to /Users/rgee0/.arkade/bin/kubectl

Wrote: /Users/rgee0/.arkade/bin/kubectl (52.59MB)
...

test-tool for kubectl

➜  arkade git:(k8sVersionStrategy) go build && ./hack/test-tool.sh kubectl
+ ./arkade get kubectl --arch arm64 --os darwin --quiet
+ file /Users/rgee0/.arkade/bin/kubectl
/Users/rgee0/.arkade/bin/kubectl: Mach-O 64-bit executable arm64
+ rm /Users/rgee0/.arkade/bin/kubectl
+ echo

+ ./arkade get kubectl --arch x86_64 --os darwin --quiet
+ file /Users/rgee0/.arkade/bin/kubectl
/Users/rgee0/.arkade/bin/kubectl: Mach-O 64-bit executable x86_64
+ rm /Users/rgee0/.arkade/bin/kubectl
+ echo

+ ./arkade get kubectl --arch x86_64 --os linux --quiet
+ file /Users/rgee0/.arkade/bin/kubectl
/Users/rgee0/.arkade/bin/kubectl: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, Go BuildID=Nw07E9mRBf9nBJc5PSDy/6xGMIBOgLhG6lkjc0Xj7/hnMF0PNvcb9-wslPJ5nh/cwX9GQu1ZeSnUp4Y2iB-, stripped
+ rm /Users/rgee0/.arkade/bin/kubectl
+ echo

+ ./arkade get kubectl --arch aarch64 --os linux --quiet
+ file /Users/rgee0/.arkade/bin/kubectl
/Users/rgee0/.arkade/bin/kubectl: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, Go BuildID=VzRAnGXpLlQctbNaLnKl/oZDpJF6tO440o8MZX2jG/RvCjxRr54MHOuPRJSrwS/dYEmNm_CirHEAgYUSdff, stripped
+ rm /Users/rgee0/.arkade/bin/kubectl
+ echo

+ ./arkade get kubectl --arch x86_64 --os mingw --quiet
+ file /Users/rgee0/.arkade/bin/kubectl.exe
/Users/rgee0/.arkade/bin/kubectl.exe: PE32+ executable (console) x86-64, for MS Windows
+ rm /Users/rgee0/.arkade/bin/kubectl.exe
+ echo

test-tool for helm since the const has been used on tools.go

➜  arkade git:(k8sVersionStrategy) go build && ./hack/test-tool.sh helm   
+ ./arkade get helm --arch arm64 --os darwin --quiet
+ file /Users/rgee0/.arkade/bin/helm
/Users/rgee0/.arkade/bin/helm: Mach-O 64-bit executable arm64
+ rm /Users/rgee0/.arkade/bin/helm
+ echo

+ ./arkade get helm --arch x86_64 --os darwin --quiet
+ file /Users/rgee0/.arkade/bin/helm
/Users/rgee0/.arkade/bin/helm: Mach-O 64-bit executable x86_64
+ rm /Users/rgee0/.arkade/bin/helm
+ echo

+ ./arkade get helm --arch x86_64 --os linux --quiet
+ file /Users/rgee0/.arkade/bin/helm
/Users/rgee0/.arkade/bin/helm: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, Go BuildID=PCzOZGnJOztKhLILw2Us/aeyDOEfwbyQa7Q7WnueN/BapdmPxG_MMNvLr4EYZe/wntKr3IhVA_px4Gr699h, stripped
+ rm /Users/rgee0/.arkade/bin/helm
+ echo

+ ./arkade get helm --arch aarch64 --os linux --quiet
+ file /Users/rgee0/.arkade/bin/helm
/Users/rgee0/.arkade/bin/helm: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, Go BuildID=Pz8WCshnh-30smNSLpDA/tRTJheJ7pA5IjAu6Qdgx/-YulxpFB4droMM4QofnO/DiFmWPiAP15uBOLCq1iP, stripped
+ rm /Users/rgee0/.arkade/bin/helm
+ echo

+ ./arkade get helm --arch x86_64 --os mingw --quiet
+ file /Users/rgee0/.arkade/bin/helm.exe
/Users/rgee0/.arkade/bin/helm.exe: PE32+ executable (console) x86-64, for MS Windows
+ rm /Users/rgee0/.arkade/bin/helm.exe
+ echo➜  arkade git:(k8sVersionStrategy) go build && ./hack/test-tool.sh helm   
+ ./arkade get helm --arch arm64 --os darwin --quiet
+ file /Users/rgee0/.arkade/bin/helm
/Users/rgee0/.arkade/bin/helm: Mach-O 64-bit executable arm64
+ rm /Users/rgee0/.arkade/bin/helm
+ echo

+ ./arkade get helm --arch x86_64 --os darwin --quiet
+ file /Users/rgee0/.arkade/bin/helm
/Users/rgee0/.arkade/bin/helm: Mach-O 64-bit executable x86_64
+ rm /Users/rgee0/.arkade/bin/helm
+ echo

+ ./arkade get helm --arch x86_64 --os linux --quiet
+ file /Users/rgee0/.arkade/bin/helm
/Users/rgee0/.arkade/bin/helm: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, Go BuildID=PCzOZGnJOztKhLILw2Us/aeyDOEfwbyQa7Q7WnueN/BapdmPxG_MMNvLr4EYZe/wntKr3IhVA_px4Gr699h, stripped
+ rm /Users/rgee0/.arkade/bin/helm
+ echo

+ ./arkade get helm --arch aarch64 --os linux --quiet
+ file /Users/rgee0/.arkade/bin/helm
/Users/rgee0/.arkade/bin/helm: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, Go BuildID=Pz8WCshnh-30smNSLpDA/tRTJheJ7pA5IjAu6Qdgx/-YulxpFB4droMM4QofnO/DiFmWPiAP15uBOLCq1iP, stripped
+ rm /Users/rgee0/.arkade/bin/helm
+ echo

+ ./arkade get helm --arch x86_64 --os mingw --quiet
+ file /Users/rgee0/.arkade/bin/helm.exe
/Users/rgee0/.arkade/bin/helm.exe: PE32+ executable (console) x86-64, for MS Windows
+ rm /Users/rgee0/.arkade/bin/helm.exe
+ echo

make e2e

➜  arkade git:(k8sVersionStrategy) make e2e
...
PASS
coverage: 60.8% of statements
ok      github.com/alexellis/arkade/pkg/get     14.943s coverage: 60.8% of statements

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Documentation

• I have updated the list of tools in README.md if (required) with ./arkade get --format markdown
• I have updated the list of apps in README.md if (required) with ./arkade install --help

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have signed-off my commits with git commit -s

• I have tested this on arm, or have added code to prevent deployment

[alexellis]

Approved