pin actions versions in CI workflow

Author: mlinksva

.github/workflows/test.yml

@@ -14,12 +14,12 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       with:
         submodules: true
 
     - name: Set up Ruby
-      uses: ruby/setup-ruby@v1
+      uses: ruby/setup-ruby@4a9ddd6f338a97768b8006bf671dfbad383215f4
       with:
         ruby-version: 3.3.4
         bundler-cache: true