Automatically request reviews from codeowners of components

[dmathieu]

We have more and more component owners who are not approvers/maintainers of the Go SIG, and are therefore not auto-assigned for review on opened PRs.

This GH Action is heavily inspired from the collector-contrib one:

• https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/.github/workflows/add-codeowners-to-pr.yml
• https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/.github/workflows/scripts/add-codeowners-to-pr.sh
• https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/.github/workflows/scripts/get-components.sh
• https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/.github/workflows/scripts/get-codeowners.sh

For every open PR, it will loop through every code owner of the components that were updated in that PR, and request a review from them, unless they were the ones opening the PR or they already reviewed the PR.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 66.7%. Comparing base (717e1db) to head (2072577).

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #6282   +/-   ##
=====================================
  Coverage   66.7%   66.7%           
=====================================
  Files        193     193           
  Lines      15565   15565           
=====================================
+ Hits       10391   10394    +3     
+ Misses      4883    4881    -2     
+ Partials     291     290    -1     

see 1 file with indirect coverage changes

[dmathieu]

This has been confirmed working on my fork.
dmathieu#1
https://github.com/dmathieu/opentelemetry-go-contrib/actions/runs/11592051616/job/32273102592?pr=1

The permissions allow modifying any PR. However, because we run on pull_request_target, changes made on a PR would not be looked into here, only the code on the main branch.
This should therefore not cause any security problem.