fix: Add the GOPATH to the go-to-protobuf command

[meeech]

This came up when trying to run the codegen. Need the GOPATH env var to be set.

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this is a chore.
• The title of the PR is (a) conventional with a list of types and scopes found here, (b) states what changed, and (c) suffixes the related issues number. E.g. "fix(controller): Updates such and such. Fixes #1234".
• I've signed my commits with DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
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[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (c5457e3) 81.75% compared to head (c5b752b) 81.75%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3022   +/-   ##
=======================================
  Coverage   81.75%   81.75%           
=======================================
  Files         134      134           
  Lines       20395    20395           
=======================================
  Hits        16674    16674           
  Misses       2865     2865           
  Partials      856      856           

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[github-actions]

Go Published Test Results

2 045 tests   2 045 ✔️  2m 40s ⏱️
   118 suites         0 💤
       1 files           0 ❌

Results for commit c5b752b.

[github-actions]

E2E Tests Published Test Results

    4 files      4 suites   3h 39m 27s ⏱️
102 tests   88 ✔️   6 💤   8 ❌
428 runs  384 ✔️ 24 💤 20 ❌

For more details on these failures, see this check.

Results for commit c5b752b.