Add Ruby 3 CI exclustions

Author: peerkleio

.github/workflows/ci.yml

@@ -19,6 +19,15 @@ jobs:
           - Gemfile.rails-6.1-stable
           - Gemfile.rails-7.0-stable
         ruby-version: ['3.1', '3.0', '2.7']
+        exclude:
+          - gemfile: Gemfile.rails-6.0-stable
+            ruby-version: "3.0"
+          - gemfile: Gemfile.rails-6.0-stable
+            ruby-version: "3.1"
+          - gemfile: Gemfile.rails-5.2-stable
+            ruby-version: "3.0"
+          - gemfile: Gemfile.rails-5.2-stable
+            ruby-version: "3.1"
     env:
       BUNDLE_GEMFILE: gemfiles/${{ matrix.gemfile }}
     steps: