ci: Test v3.0.0 in CI

Author: sondrelg

.github/workflows/live_test.yaml

@@ -23,7 +23,7 @@ jobs:
           digest=$(docker manifest inspect ghcr.io/snok/container-retention-policy:v3.0.0 | jq -r '.manifests[].digest' | paste -s -d ' ' -)
           echo "multi-arch-digests=$digest" >> $GITHUB_OUTPUT
 
-      - uses: snok/container-retention-policy@main
+      - uses: snok/container-retention-policy@v3.0.0
         name: Delete test-1-* images with a temporal token
         with:
           account: snok