Stricter lint rules

[jkroepke]

What this PR does / why we need it

Which issue this PR fixes

(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

• fixes #

Special notes for your reviewer

Particularly user-facing changes

Checklist

Complete these before marking the PR as ready to review:

• DCO signed
• The PR title has a summary of the changes
• The PR body has a summary to reflect any significant (and particularly user-facing) changes introduced by this PR

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 4 lines in your changes missing coverage. Please review.

Project coverage is 82.70%. Comparing base (31f9f18) to head (a5f2bdb).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/oauth2/provider.go	71.42%	2 Missing ⚠️
internal/oauth2/providers/github/api.go	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #377      +/-   ##
==========================================
- Coverage   82.73%   82.70%   -0.04%     
==========================================
  Files          51       51              
  Lines        3163     3162       -1     
==========================================
- Hits         2617     2615       -2     
- Misses        416      418       +2     
+ Partials      130      129       -1     

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