Bump pghero from 2.7.2 to 2.7.3 (#15250)

Bumps [pghero](https://github.com/ankane/pghero) from 2.7.2 to 2.7.3.
- [Release notes](https://github.com/ankane/pghero/releases)
- [Changelog](https://github.com/ankane/pghero/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ankane/pghero/compare/v2.7.2...v2.7.3)

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

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

Gemfile.lock

@@ -403,7 +403,7 @@ GEM
     pastel (0.8.0)
       tty-color (~> 0.5)
     pg (1.2.3)
-    pghero (2.7.2)
+    pghero (2.7.3)
       activerecord (>= 5)
     pkg-config (1.4.4)
     pluck_each (0.1.3)
@@ -634,7 +634,7 @@ GEM
     tty-screen (0.8.1)
     twitter-text (1.14.7)
       unf (~> 0.1.0)
-    tzinfo (1.2.7)
+    tzinfo (1.2.8)
       thread_safe (~> 0.1)
     tzinfo-data (1.2020.4)
       tzinfo (>= 1.0.0)