build(deps): bump pg from 1.5.7 to 1.5.8 (#6042)

Bumps [pg](https://github.com/ged/ruby-pg) from 1.5.7 to 1.5.8.
- [Changelog](https://github.com/ged/ruby-pg/blob/master/History.md)
- [Commits](ged/ruby-pg@v1.5.7...v1.5.8)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -354,7 +354,7 @@ GEM
       cliver (~> 0.3.2)
       rexml (~> 3.2, >= 3.2.6)
       safe_shell (>= 1.0.3, < 2.0)
-    pg (1.5.7)
+    pg (1.5.8)
     pretender (0.5.0)
       actionpack (>= 6.1)
     pry (0.14.2)