ci(actions): enhance Docker build process with buildx setup

- Adds setup for Docker Buildx to enable multi-platform builds.
- Ensures Docker login step only runs for relevant GitHub events.

Author: winromulus

.github/workflows/main.yaml

@@ -55,12 +55,16 @@ jobs:
           path: .artifacts/kubectl
 
       - name: tools - docker - login
-        if: github.event_name == 'push' && github.actor != 'dependabot[bot]'
         uses: docker/login-action@v3
         with:
           username: ${{ secrets.ES_DOCKERHUB_USERNAME }}
           password: ${{ secrets.ES_DOCKERHUB_PAT }}
 
+      - name: docker - setup - buildx
+        uses: docker/setup-buildx-action@v3
+        with:
+          driver: docker-container  # REQUIRED for multi-platform builds
+
       - name: docker - build and push
         uses: docker/build-push-action@v5
         with: