doc: update googleapis howto

[scotthart]

No description provided.

[gemini-code-assist]

Code Review

This pull request updates the contributor guide for updating the googleapis SHA by adding instructions on how to update the googleapis BCR module and updating the usage of the renovate.sh script. The review feedback recommends clarifying a placeholder path in the BCR publishing script command to ensure it correctly references a local clone of the repository.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.24%. Comparing base (694b229) to head (5725b3c).

Additional details and impacted files

@@ Coverage Diff @@## main #16352 +/- ##
=======================================
Coverage 92.23% 92.24% =======================================
Files 2227 2227 Lines 209543 209543 =======================================
+ Hits 193282 193288 +6 + Misses 16261 16255 -6 

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.