Bump docker/build-push-action from 5 to 6

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 5 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v5...v6)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/push.yml

@@ -21,7 +21,7 @@ jobs:
         id: buildx
         uses: docker/setup-buildx-action@master
       - name: Build HTTPS proxy (${{ matrix.platform }})
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           file: "Dockerfile"
           builder: ${{ steps.buildx.outputs.name }}

.github/workflows/release.yml

@@ -31,7 +31,7 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.PAT_TOKEN }}
       - name: Build HTTPS proxy
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           file: "Dockerfile"
           builder: ${{ steps.buildx.outputs.name }}