DEV: Bump pg from 1.2.0 to 1.2.1 (#8657)

Bumps [pg](https://github.com/ged/ruby-pg) from 1.2.0 to 1.2.1.
- [Release notes](https://github.com/ged/ruby-pg/releases)
- [Changelog](https://github.com/ged/ruby-pg/blob/master/History.rdoc)
- [Commits](https://github.com/ged/ruby-pg/compare/v1.2.0...v1.2.1)

Very minor update, adds some functionality we do not use, specifically better support for the sequel orm.

Gemfile.lock

@@ -258,7 +258,7 @@ GEM
       parallel
     parser (2.7.0.1)
       ast (~> 2.4.0)
-    pg (1.2.0)
+    pg (1.2.1)
     progress (3.5.2)
     pry (0.12.2)
       coderay (~> 1.1.0)