[TASK] Update actions/cache to v2

Author: gilbertsoft

.github/workflows/continuous-integration.yml

@@ -36,9 +36,10 @@ jobs:
 
       - name: Get Composer Cache Directory
         id: composer-cache
-        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+        run: |
+          echo "::set-output name=dir::$(composer config cache-files-dir)"
 
-      - uses: actions/cache@v1
+      - uses: actions/cache@v2
         with:
           path: ${{ steps.composer-cache.outputs.dir }}
           key: ${{ matrix.php }}-composer-${{ hashFiles('**/composer.lock') }}