Align github CI matrix with supported rubies

Author: mjankowski

.github/workflows/test.yml

@@ -15,7 +15,11 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        ruby-version: [2.7, '3.0', 3.1, 3.2]
+        ruby-version:
+          - "3.0"
+          - "3.1"
+          - "3.2"
+          - "3.3"
 
     runs-on: ${{ matrix.os }}