separate scanning into own job

.github/workflows/ci.yml

@@ -138,6 +138,17 @@ jobs:
           tags: |
             ghcr.io/fkie-cad/logprep:py${{ matrix.python-version }}-${{ github.head_ref }}
 
+  trivy-scan:
+    runs-on: ubuntu-latest
+    needs: containerbuild
+    steps:
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       # To avoid the trivy-db becoming outdated, we save the cache for one day
       - name: Get date
         id: date