Update docker/build-push-action action to v6.18.0 (#1756)

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

Author: renovate[bot]

.github/workflows/publish-otel-php-base-docker-image.yml

@@ -40,7 +40,7 @@ jobs:
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build and push ${{ matrix.php-version }} to ghcr.io
-        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6
+        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
         if: github.ref != 'refs/heads/main'
         with:
           push: false
@@ -49,7 +49,7 @@ jobs:
           platforms: linux/amd64,linux/arm/v8,linux/arm64
 
       - name: Build and push ${{ matrix.php-version }} to ghcr.io
-        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6
+        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
         if: github.ref == 'refs/heads/main'
         with:
           push: true