Update docker/build-push-action action to v7

Author: renovate[bot]

.github/workflows/docker-build.yml

@@ -60,7 +60,7 @@ jobs:
 
       - name: Build and push base image (digest)
         id: build-base
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@v7
         with:
           context: .
           target: base
@@ -71,7 +71,7 @@ jobs:
 
       - name: Build and push tmux image (digest)
         id: build-tmux
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@v7
         with:
           context: .
           target: tmux