Update labkit of updated pgquery
Update labkit to v.0.34.0
This updates labkit, which includes an updated pgquery.
This fixes the build with glibc 2.38: https://github.com/pganalyze/pg_query/issues/298
This is following the community contribution by @vrein in gitlab-org/ruby/gems/labkit-ruby!116 (merged)
Edited by Bob Van Landuyt