chore(gapicgen): update Go microgen to v0.23.0 (#4649)
chore(gapicgen): update Go microgen to v0.23.0 (#4649)

Updates Go GAPIC generator to v0.23.0. This carries a breaking change for 4 Compute RPCs, switching them back to the raw proto Operation type instead of the wrapped operations. This is intended.

This update also includes several example and pkg doc updates. 
googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go