ci: broaden Trivy scan scope and simplify output format

- Change Trivy output format from SARIF to table and remove SARIF output file
- Include MEDIUM severity in vulnerability scan

Signed-off-by: appleboy <appleboy.tw@gmail.com>

Author: appleboy

.github/workflows/testing.yml

@@ -75,7 +75,6 @@ jobs:
         with:
           scan-type: 'fs'
           ignore-unfixed: true
-          format: 'sarif'
-          output: 'trivy-results.sarif'
+          format: 'table'
           exit-code: '1'
-          severity: 'CRITICAL,HIGH'
+          severity: 'CRITICAL,HIGH,MEDIUM'