use commit hash for hashicorp/setup-terraform@v2

Author: ncooke3

.github/workflows/firestore.yml

@@ -205,7 +205,7 @@ jobs:
     - name: Set up Google Cloud SDK
       uses: google-github-actions/setup-gcloud@v1
     - name: Setup Terraform
-      uses: hashicorp/setup-terraform@v2
+      uses: hashicorp/setup-terraform@633666f66e0061ca3b725c73b2ec20cd13a8fdd1
     - name: Terraform Init
       run: |
         cd Firestore