Pin third-party GitHub Actions to full commit SHAs (#99)

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: devin-ai-integration[bot]

.github/workflows/python-app.yml

@@ -18,9 +18,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744  # v3
     - name: Set up Python 3.10
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@3542bca2639a428e1796aaa6a2ffef0c0f575566  # v3
       with:
         python-version: "3.10"
     - name: Install dependencies