Correct regex match field according to docs (#520)
Correct regex match field according to docs (#520)

Changes made since last time:
* Target the "regex" manager in the packageRules rule.
* Put `fileMatch` at the top level, where it should be.
* Put `regexManagers` at the top level, where it should be.
* Adjust the regex to handle both deps with submodules (`//`) and without.
GoogleCloudPlatform/solution-acceleration-toolkit,GoogleCloudPlatform/solution-acceleration-toolkit