Fixes for complex predefined field types (#210)

Updates the protovalidate version to 0.8.2 and fixes three
closely-related bugs:
- `rule` is inadvertently typed incorrectly when it is a repeated rule
field on a repeated field
- `getCELType` inadvertently returns an incorrectly-named message type
when dealing with a message field (using the full name of the field
instead of the full name of the type)
- `getCELType` returns a message type instead of a wrapper type for
wrappers like `google.protobuf.Int32Value`

These bugs are subtle because they don't occur in normal circumstances,
but the new predefined rule tests added in v0.8.2 to close the bugs on
protovalidate-go inadvertently revealed several protovalidate-java bugs.
This validates that more work on the conformance test can still be quite
valuable in finding difficult bugs, even if we don't know exactly what
we're looking for.