[CI] Bump docker/setup-buildx-action from 3 to 4 (#7542)

Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 3 to 4.

- vLLM version: v0.18.0
- vLLM main:
8b6325758c

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

.github/workflows/_schedule_image_build.yaml

@@ -70,7 +70,7 @@ jobs:
         password: ${{ secrets.QUAY_PASSWORD }}
 
     - name: Set up Docker Buildx
-      uses: docker/setup-buildx-action@v3
+      uses: docker/setup-buildx-action@v4
       with:
         install: true
         driver: docker-container
@@ -168,7 +168,7 @@ jobs:
           password: ${{ secrets.QUAY_PASSWORD }}
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@v4
 
       - name: Merge and push multi-arch image
         env:

.github/workflows/schedule_lint_image_build.yaml

@@ -50,7 +50,7 @@ jobs:
       uses: docker/setup-qemu-action@v3
 
     - name: Build - Set up Docker Buildx
-      uses: docker/setup-buildx-action@v3
+      uses: docker/setup-buildx-action@v4
 
     - name: Publish - Login to Quay Container Registry
       if: ${{ github.repository_owner == 'vllm-project' }}