Improve developer experience for testing draft PRs

[gberche-orange]

Expected behavior

As a developper,
in order to test a draft PR,
I need to easily download the dev release tgz file stored as github action build artefact from a bastion container to perform bosh upload release command

Observed behavior

• Bastion container has no web browser to download from github web ui
• Download Uris require github auth
• github cli has no yet support for downloading workflow artefacts
  • Support for viewing, managing, and accessing workflow artifacts cli/cli#6532
  • Support downloading artifacts in the current session cli/cli#8641

workaround

From cli/cli#6532

git clone https://github.com/orange-cloudfoundry/k3s-wrapper-boshrelease.git
cd k3s-wrapper-boshrelease/
gh auth login

#> ? Where do you use GitHub? GitHub.com
#> ? What is your preferred protocol for Git operations on this host? HTTPS
#> ? Authenticate Git with your GitHub credentials? No
#> ? How would you like to authenticate GitHub CLI? Login with a web browser
#> 
#> ! First copy your one-time code: [...]
#> Press Enter to open github.com in your browser... 
#> Simulating browser invocation from xdg-open call with params: https://github.com/login/device

# NOTE: Must redirect output to file as `gh api` will follow redirect and stream binary data
gh api /repos/{owner}/{repo}/actions/artifacts/416002865/zip > 416002865.zip

Possible fix

• create one draft github release for each github action build for PR e.g. <branch-name>.<commit_hash>
• delete draft github releases <branch-name>.* when a PR gets merged