Updates docker/setup-buildx-action and pins to 4d04d5d9486b7bd6fa91e7baf45bbb4f8b9deedd

Updates docker/setup-buildx-action from v3 to v4.0.0 and pins to a specific commit hash instead of the tag.

Author: Alex-Welsh

.github/workflows/stackhpc-build-kayobe-image.yml

@@ -69,7 +69,7 @@ jobs:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@4d04d5d9486b7bd6fa91e7baf45bbb4f8b9deedd # v4.0.0
         with:
           driver-opts: |
             image=moby/buildkit:master