Pass table to format templated endpoint

[wd60622]

Describe what this PR does / why we need it

Closes #821

Use the format parameter to format a templated endpoint string

local gh = require "octo.gh"

local endpoint = "/repos/{owner}/{repo}/issues/{issue_number}"

local opts = { cb = gh.create_callback {} }

gh.api.get { 
  endpoint, 
  format = { owner = "pwntester", repo = "octo.nvim", issue_number = 1 },
  jq = "{ title, body, author: .user.login }",
  opts = opts,
}

However, the format parameter is not required. If it is not provided, the endpoint string is used as is (current behavior).

local gh = require "octo.gh"

local endpoint = "/repos/pwntester/octo.nvim/issues/1"

local opts = { cb = gh.create_callback {} }

gh.api.get { 
  endpoint, 
  jq = "{ title, body, author: .user.login }",
  opts = opts,
}

CC: @ldelossa

Does this pull request fix one issue?

Describe how you did it

Describe how to verify it

Special notes for reviews

Checklist

• Passing tests and linting standards
• Documentation updates in README.md and doc/octo.txt

[ldelossa]

Awesome!

[wd60622]

How is the name? Make sense or is something else better?

[ldelossa]

Which name

[wd60622]

Using format as the designated keyword. Something better suited?

One parallel with api.graph is the fields parameter. That acts as the values which will be substituted into graphql query. For example,

local gh = require "octo.gh"

local query = [[
query($login: String!) {
  user(login: $login) {
    id
  }
}
]]

local opts = { cb = gh.create_callback {} }

gh.api.graphql {
  query = query,
  fields = { login = "wd60622" },
  opts = opts,
}

fields play a bit different role in call than format but the idea is similar.

[ldelossa]

I like either! Fields is prob a bit better.