Cop/GemFetcher: Refactor and link to development guide

Peter Leitzenrequested to merge
cop-gem-fetcher-link into master

What does this MR do and why?

This MR refactors the 👮 Cop/GemFetcher and adds link to development guide (see gitlab-org/gitlab!107224 (merged)).

The refactor reasoning:

  • Support more git source like bitbucket and gist
  • Use RuboCop's Include directive instead of checking filename
  • Use RuboCop's node pattern to reduce code
  • Use RESTRICT_ON_SEND to speed up the check
Edited by Peter Leitzen

Merge request reports