Fix certora run action's version

Author: aehyvari

.github/workflows/certora-prover.yml

@@ -55,8 +55,9 @@ jobs:
           # Use dev branch for scheduled runs, otherwise use the branch that triggered the workflow
           ref: ${{ github.event_name == 'schedule' && 'dev' || github.ref }}
 
-      - name: Submit verification jobs to Certora Prover
-        uses: Certora/certora-run-action@v2
+      # Run Certora compilation and verification
+      - name: Run Certora compilation and verification
+        uses: Certora/certora-run-action@11979c68d2ffab0b1b2fe6c72ec9d7a38855822d
         with:
           # List of configuration files for different contracts to verify
           configurations: |-