build(deps): bump aquasecurity/trivy-action from 0.20.0 to 0.21.0

Bumps [aquasecurity/trivy-action](https://github.com/aquasecurity/trivy-action) from 0.20.0 to 0.21.0.
- [Release notes](https://github.com/aquasecurity/trivy-action/releases)
- [Commits](aquasecurity/trivy-action@b2933f5...fd25fed)

---
updated-dependencies:
- dependency-name: aquasecurity/trivy-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/release.yaml

@@ -60,7 +60,7 @@ jobs:
         run: |
           docker load < /tmp/etcd-img.tar
       - name: trivy-scan
-        uses: aquasecurity/trivy-action@b2933f565dbc598b29947660e66259e3c7bc8561 # v0.20.0
+        uses: aquasecurity/trivy-action@fd25fed6972e341ff0007ddb61f77e88103953c2 # v0.21.0
         with:
           image-ref: 'gcr.io/etcd-development/etcd:v3.6.99-${{ matrix.platforms }}'
           severity: 'CRITICAL,HIGH'