Release: rules_java 7.9.1

[comius]

Link to relevant issue and/or commit:

java/private/proto_support.bzl is botched in the latest release 7.9.0
https://github.com/bazelbuild/rules_java/tree/7.9.0/java/private

Main branch looks fine.

Other details:

cc @bazelbuild/triage

[keertk]

https://github.com/bazelbuild/rules_java/releases/tag/7.9.1
bazelbuild/bazel-central-registry#2705