Update actions/cache action to v4

| datasource  | package       | from | to |
| ----------- | ------------- | ---- | -- |
| github-tags | actions/cache | v3   | v4 |

Author: renovate[bot]

.github/workflows/continuous-integration.yml

@@ -65,7 +65,7 @@ jobs:
           tools: composer:v2
 
       - name: "Cache dependencies"
-        uses: "actions/cache@v3"
+        uses: "actions/cache@v4"
         with:
           path: |
             ~/.composer/cache
@@ -118,7 +118,7 @@ jobs:
           tools: composer:v2
 
       - name: "Cache dependencies"
-        uses: "actions/cache@v3"
+        uses: "actions/cache@v4"
         with:
           path: |
             ~/.composer/cache