ci: add composer dependency caching

Author: shimomo

.github/workflows/cron.yml

@@ -28,6 +28,18 @@ jobs:
         with:
           fetch-depth: 0
 
+      - name: Get Composer cache directory
+        id: composer-cache
+        run: echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
+
+      - name: Cache Composer dependencies
+        uses: actions/cache@0400d5f644dc74513175e3cd8d07132dd4860809
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          key: ${{ runner.os }}-php-${{ hashFiles('**/composer.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-php-
+
       - name: Install base dependencies (without scraper)
         run: |
           composer remove bvp/scraper --no-update || true