SHA pinning (#3928)

Author: shargon

.github/workflows/main.yml

@@ -94,7 +94,7 @@ jobs:
 
     - name: Coveralls
       if: matrix.os == 'ubuntu-latest'
-      uses: coverallsapp/github-action@v2.3.6
+      uses: coverallsapp/github-action@648a8eb78e6d50909eff900e4ec85cab4524a45b
       with:
         github-token: ${{ secrets.GITHUB_TOKEN }}
         debug: false