MINOR:Add 4.2.1 to docker_scan workflow

Signed-off-by: PoAn Yang <payang@apache.org>

Author: FrankYang0529

.github/workflows/docker_scan.yml

@@ -26,7 +26,7 @@ jobs:
     strategy:
       matrix:
         # This is an array of supported tags. Make sure this array only contains the supported tags
-        supported_image_tag: ['latest', '3.9.2', '4.0.2', '4.1.2', '4.2.0', '4.3.0']
+        supported_image_tag: ['latest', '3.9.2', '4.0.2', '4.1.2', '4.2.1', '4.3.0']
     steps:
       - name: Run CVE scan
         uses: lhotari/sandboxed-trivy-action@555963036b2012b44c1071508a236e569db28ebb # v1.0.1