Set full ruby version to tests matrix

.github/workflows/tests.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [3.0, 3.1, 3.2, 3.3]
+        ruby: [3.0.7, 3.1.6, 3.2.5, 3.3.5]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Ruby