reflex upgrade should add new configuration variables for rules when they get added

[mcbanderson]

Currently, running reflex upgrade will only bump rule versions in reflex.yaml, but if new configuration variables were added to the rule these are not added to reflex.yaml. This doesn't break anything for minor version increases in rules (which would occur if the new variable has a default value provided), but could break rules if there was a major version bump that required new configuration variables.

To fix this we should have reflex upgrade include any new configuration options when bumping the rule version, or provide a flag for triggering this functionality.

To test this we can use the change from s3-bucket-not-encrypted going from v2.1.9 -> v2.2.0, which added the encryption_key configuration variable.