Bump pghero from 2.6.0 to 2.7.0 (#14518)

Bumps [pghero](https://github.com/ankane/pghero) from 2.6.0 to 2.7.0.
- [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/v2.6.0...v2.7.0)

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

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

Gemfile.lock

@@ -405,7 +405,7 @@ GEM
     pastel (0.8.0)
       tty-color (~> 0.5)
     pg (1.2.3)
-    pghero (2.6.0)
+    pghero (2.7.0)
       activerecord (>= 5)
     pkg-config (1.4.1)
     posix-spawn (0.3.15)
@@ -738,7 +738,7 @@ DEPENDENCIES
   parallel_tests (~> 3.1)
   parslet
   pg (~> 1.2)
-  pghero (~> 2.6)
+  pghero (~> 2.7)
   pkg-config (~> 1.4)
   posix-spawn
   premailer-rails