feat: Update govulncheck integration and enable CGO there

[another-rex]

#1443

This will solve the above issue, but let's not close it until the release is out.

The disabling CGO env flag can be removed as it seems like govulncheck will successfully analyse CGO projects, just not actually do analysis on the C parts.

The comment about:

This still leaves govulncheck enabled for non C related calls.

It is only partially true, as if the C parts are required to compile the application, if CGO is disabled, it cannot compile successfully.

We'll need to cherrypick this change into main after this is merged.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.05%. Comparing base (1e295ee) to head (745d817).

Additional details and impacted files

@@            Coverage Diff             @@
##               v1    #1478      +/-   ##
==========================================
- Coverage   69.05%   69.05%   -0.01%     
==========================================
  Files         186      186              
  Lines       18346    18344       -2     
==========================================
- Hits        12669    12667       -2     
  Misses       5012     5012              
  Partials      665      665              

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