Upgrade Gradle Witness

Gradle Witness can only handle dependencies declared with the compile configuration. I patched it to handle all configurations that are resolvable at the time the plugin runs, which allows us verify more of the code we depend on. This also allows us to use new configurations that have been added to the Android and Java Library plugins, such as implementation, which speeds up build times by reducing transitive dependencies.

I've changed the format Gradle Witness uses for declaring dependency hashes, as the old format didn't unambiguously identify all dependencies (a dependency can be present in one or more versions, with one or more files per version).