Bump pkg-config from 1.5.7 to 1.5.8

Bumps [pkg-config](https://github.com/ruby-gnome/pkg-config) from 1.5.7 to 1.5.8.
- [Release notes](https://github.com/ruby-gnome/pkg-config/releases)
- [Changelog](https://github.com/ruby-gnome/pkg-config/blob/main/NEWS.md)
- [Commits](ruby-gnome/pkg-config@1.5.7...1.5.8)

---
updated-dependencies:
- dependency-name: pkg-config
  dependency-type: indirect
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -40,7 +40,7 @@ GEM
       hashery (~> 2.0)
       ruby-rc4
       ttfunk
-    pkg-config (1.5.7)
+    pkg-config (1.5.8)
     racc (1.8.1)
     rainbow (3.1.1)
     rake (13.2.1)