Update docker/build-push-action action to v6.18.0 (#805)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/build-docker.yml

@@ -85,7 +85,7 @@ jobs:
       # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/
       - name: Build and push by digest
         id: build
-        uses: docker/build-push-action@14487ce63c7a62a4a324b0bfb37086795e31c6c1 # v6
+        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
         with:
           context: .
           platforms: ${{ matrix.platform }}
@@ -238,7 +238,7 @@ jobs:
             ${{ env.TAG_PATTERNS }}
 
       - name: Build and push
-        uses: docker/build-push-action@14487ce63c7a62a4a324b0bfb37086795e31c6c1 # v6
+        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
         with:
           context: .
           platforms: linux/amd64,linux/arm64