Due to https://github.com/protocolbuffers/protobuf/issues/8559,
google-protobuf v3.15.8 can seg fault in the FindCommits RPC call if the
options hash is garbage collected before gRPC encodes the message. This
was fixed in google-protobuf v3.17.1 via
https://github.com/protocolbuffers/protobuf/pull/8639.

Unfortunately, pg_query has a hard dependency on google-protobuf
v3.15.x.  This was bumped in
https://github.com/pganalyze/pg_query/pull/212, but an official version
has not yet been tagged.

In addition, https://github.com/pganalyze/pg_query/pull/213 would relax
the dependency so that google-protobuf can be upgraded without having to
update pg_query.

Until pg_query releases a new version, we use our fork to ensure this
seg fault cannot happen.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/330998

Changelog: fixed