Bump docker/build-push-action from 5.3.0 to 6.18.0 (#1259)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 5.3.0 to 6.18.0.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@2cdde99...2634353)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-version: 6.18.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -377,7 +377,7 @@ jobs:
         run: echo "GO_VERSION=$(cat go.mod | grep toolchain | sed 's/toolchain //; s/go//')" >> $GITHUB_ENV
 
       - name: Build Docker Image
-        uses: docker/build-push-action@2cdde995de11925a030ce8070c3d77a52ffcf1c0 # v5.3.0
+        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
         env:
           GO_VERSION: ${{ env.GO_VERSION }}
         with:

.github/workflows/release-branch.yml

@@ -236,7 +236,7 @@ jobs:
         uses: docker/setup-buildx-action@d70bba72b1f3fd22344832f00baa16ece964efeb # v3.3.0
 
       - name: Build Docker Image
-        uses: docker/build-push-action@2cdde995de11925a030ce8070c3d77a52ffcf1c0 # v5.3.0
+        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
         with:
           file: scripts/packages/packager/Dockerfile
           tags: build-signed-packager:1.0.0