rspec.yml in groupie-0.5.0

- old
+ new

@@ -5,12 +5,13 @@
 jobs:
   build:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        # Maintained versions: 2.7 and 3.0
-        # Security updates only: 2.6
-        ruby: [ 2.6, 2.7, 3.0 ]
+        # Maintained versions: 2.7, 3.0, 3.1
+        # Security updates only: 2.6 (EOL: 2022-03-31)
+        # Source: https://www.ruby-lang.org/en/downloads/branches/
+        ruby: [ 2.6, 2.7, 3.0, 3.1 ]
     steps:
       - uses: actions/checkout@v2
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with: