Chore: compact `GitHub` repo `URL` e.g: `https://github.com/dwyl/link/`

[nelsonic]

As noted by @LuchoTurtle in #5 (review) the repo URL https://github.com/dwyl/link is not compacted:

Todo

• Review the existing tests for repo URLs:
  

  link/lib/link.ex

  Lines 41 to 54 in ae0127d

  	## Examples
  	iex> Link.compact_github_url("https://github.com/dwyl/mvp/issues/141")
  	"dwyl/mvp#141"
  	iex> Link.compact_github_url("https://github.com/dwyl/app/issues/275#issuecomment-1646862277")
  	"dwyl/app#275"
  	iex> Link.compact_github_url("https://github.com/dwyl/link#123")
  	"dwyl/link"
  	iex> Link.compact_github_url("https://github.com/dwyl/link/pull/5")
  	"dwyl/link/PR#5"
  	"""

  
  Currently no doctest or specific test for just the repo URL ...
• Create doctest for just the base URL https://github.com/dwyl/link/ should compact to: dwyl/link
• Make the doctest pass without breaking any existing tests.
• Bump version in mix.exs and README.md to release the fix.
• Create PR & assign for review
• Publish to hex.pm