Support multiple regions

[andmarios]

TL;DR

Cloud Run supports multiple regions, so this action should as well. :)

Detailed design

Currently, the code always applies the --region flag to the gcloud command. I think there are two cases:

1. When we use gcloud run deploy, if there are multiple regions, the --regions flag should be used instead of --region.
2. When we use gcloud run replace (with a metadata file), we should trust the metadata file to define the regions and drop --region, since the replace command does not support the --regions flag.

Additional information

No response