renovate.sh ignores real failures in `generate-libraries.sh`
We use renovate.sh to update the googleapis SHA. It automatically updates the generated code too:
https://github.com/googleapis/google-cloud-cpp/blob/682e0657e270533675163dca54a722526aaae145/external/googleapis/renovate.sh#L72-L75
The || true is needed because generate-libraries.sh is intended as a CI script. It is supposed to fail if the code does not match what would happen if we generated the code, and in this case we always generate new code.
It seems we need a way to tell generate-libraries.sh to expect code diffs. Or maybe we should refactor the code such that both renovate.sh and generate-libraries.sh call some shell functions.
I don't love this, but we could run ci/cloudbuild/build.sh -t generate-libraries-pr a second time before exiting the script.