Bump pkg-config from 1.3.0 to 1.3.1 (#8788)

Bumps [pkg-config](https://github.com/ruby-gnome2/pkg-config) from 1.3.0 to 1.3.1.
- [Release notes](https://github.com/ruby-gnome2/pkg-config/releases)
- [Changelog](https://github.com/ruby-gnome2/pkg-config/blob/master/NEWS)
- [Commits](https://github.com/ruby-gnome2/pkg-config/compare/1.3.0...1.3.1)

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

Gemfile.lock

@@ -393,7 +393,7 @@ GEM
     pg (1.0.0)
     pghero (2.2.0)
       activerecord
-    pkg-config (1.3.0)
+    pkg-config (1.3.1)
     powerpack (0.1.1)
     premailer (1.11.1)
       addressable