Cloudrun v9 migration guide updates

Changes:

• Added disable_monitoring renaming to the list of changes input variables in both the how-to and the explanation.
• Added a couple of links from the how-to to the explanation.
• Expanded the Domain mapping explanation to warn about change of automatically assigned URLs
• Added --build flag to docker compose example.

assigned to @jb2595

requested review from @amc203

Thanks for updating the documentation @jb2595!

approved this merge request

mentioned in commit e172fd2e

merged

mentioned in merge request !459 (merged)