tests.yaml in openactive-0.4.0

- old
+ new

@@ -10,10 +10,10 @@
   test:
 
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['2.6', '2.7']
+        ruby-version: ['2.7', '3.0', '3.1']
 
     steps:
     - uses: actions/checkout@v2
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1