build: opt to set progress warnings in response

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

.github/workflows/e2e.yml

@@ -84,6 +84,8 @@ jobs:
             endpoint: tcp://localhost:1234
           - driver: docker-container
             metadata-provenance: max
+          - driver: docker-container
+            metadata-warnings: true
         exclude:
           - driver: docker
             multi-node: mnode-true
@@ -134,6 +136,9 @@ jobs:
           if [ -n "${{ matrix.metadata-provenance }}" ]; then
             echo "BUILDX_METADATA_PROVENANCE=${{ matrix.metadata-provenance }}" >> $GITHUB_ENV
           fi
+          if [ -n "${{ matrix.metadata-warnings }}" ]; then
+            echo "BUILDX_METADATA_WARNINGS=${{ matrix.metadata-warnings }}" >> $GITHUB_ENV
+          fi
       -
         name: Install k3s
         if: matrix.driver == 'kubernetes'