[CI] bump actions/cache

Author: GuillaumeDSM

.github/workflows/docker.yml

@@ -53,7 +53,7 @@ jobs:
           use: true
 
       - name: Cache Docker layers
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: /tmp/.buildx-cache
           key: ${{ runner.os }}-buildx-${{ github.sha }}