Backport of ci: Single source of truth for Go version in CI and Dockerfile into release/1.17.x

[zalimeni]

Manual backport of #20058 to release/1.17.x.

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern

Overview of commits

• 521493732f3f36908845751a978b4a88e1690301

[curtbushko]

LGTM.

I think just to make backports easier on these files it is ok to include the other 2 files:

nightly-test-integ-peering_commontopo.yml
nightly-test-integrations-1.17.x.yml

At least for these files they won't be triggered because cron jobs only start off of main.

[zalimeni]

I think just to make backports easier on these files it is ok to include the other 2 files:

nightly-test-integ-peering_commontopo.yml
nightly-test-integrations-1.17.x.yml

At least for these files they won't be triggered because cron jobs only start off of main.

@curtbushko hmm, that's a fair point. I kept it status-quo in this change, but it might be worthwhile to add them down the chain. I might do that as a follow-up since these PRs are already green, if that works for you.

Thanks for the review!