gh: pull trivy-db from AWS registry

The default ghcr.io registry for trivy-db "image" gets frequent
"toomanyrequest" rate-limiting errors and blocks our workflows.

Until that gets properly fixed, move to use an alternative repository
provided by Aqua Security.

Signed-off-by: Mikko Ylinen <[email protected]>

Author: mythi

.github/workflows/lib-trivy.yaml

@@ -90,6 +90,8 @@ jobs:
         list-all-pkgs: true
         format: json
         output: trivy-report.json
+      env:
+        TRIVY_DB_REPOSITORY: public.ecr.aws/aquasecurity/trivy-db
     - name: Show report in human-readable format
       uses: aquasecurity/trivy-action@915b19bbe73b92a6cf82a1bc12b087c9a19a5fe2 # 0.28.0
       with: