* Convert to gradle 7.
* More fixes, regenerated lockfiles.
* Update lockfiles for dependency update.
* Fix show_upgrade_diff for new lockfile format
* Add property for allowInsecureProtocol
Allow us to override the restriction against use of plain HTTP for
communication to dependency repositories. We need this to be able to use a
local proxy for dependency gathering.
* Checking in missing gradle.lockfile
* Add test for Java 8 Compatibility
Add a test to check for Java 8 compatibility of jars deployed to
AppEngine.
It is not enough to run existing tests with Java 8 VM, since many API
jars are not exercised by tests. For example, those for GCP services
like the SecretManager.
We take the conservative approach and verify that every class in every
jar are compiled for Java 8.
