Bump pg from 1.5.8 to 1.5.9

Bumps [pg](https://github.com/ged/ruby-pg) from 1.5.8 to 1.5.9.
- [Changelog](https://github.com/ged/ruby-pg/blob/master/History.md)
- [Commits](ged/ruby-pg@v1.5.8...v1.5.9)

---
updated-dependencies:
- dependency-name: pg
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -303,7 +303,7 @@ GEM
     parser (3.3.5.0)
       ast (~> 2.4.1)
       racc
-    pg (1.5.8)
+    pg (1.5.9)
     proformaxml (1.5.1)
       activemodel (>= 5.2.3, < 8.0.0)
       activesupport (>= 5.2.3, < 8.0.0)