Update checkout action version

Author: CodingAnarchy

.github/workflows/gem-push.yml

@@ -11,11 +11,11 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
-    - name: Set up Ruby 3.1
+    - uses: actions/checkout@v4
+    - name: Set up Ruby 3.3
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 3.1
+        ruby-version: 3.3
 
     - name: Publish to GPR
       run: |