Bump pg from 1.5.7 to 1.5.8 (#7)

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

@@ -212,8 +212,8 @@ GEM
       oauth2 (>= 1.4, < 3)
       omniauth (~> 2.0)
     orm_adapter (0.5.0)
-    pg (1.5.7)
-    pg (1.5.7-x64-mingw32)
+    pg (1.5.8)
+    pg (1.5.8-x64-mingw32)
     psych (5.1.2)
       stringio
     puma (6.4.2)