Group asdf version with ruby

For some reason, the package is called "ruby-version"?

renovate.json

@@ -15,6 +15,7 @@
       ],
       "matchPackageNames": [
         "ruby",
+        "ruby-version",
         "mcr.microsoft.com/devcontainers/ruby",
         "registry.docker.com/library/ruby"
       ],