Update google-protobuf to v3.17.1

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 #330998 (closed)