Bump aquasecurity/trivy-action from 0.20.0 to 0.21.0 (#35)

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@0.20.0...0.21.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build.yml

@@ -29,7 +29,7 @@ jobs:
         file: Dockerfile
 
     - name: Run Trivy vulnerability scanner
-      uses: aquasecurity/trivy-action@0.20.0
+      uses: aquasecurity/trivy-action@0.21.0
       with:
         image-ref: rancher/hardened-whereabouts:${{ env.TAG }}-amd64
         ignore-unfixed: true