Cache Composer dependencies

Author: Alexander Obuhovich

.github/workflows/main.yml

@@ -47,6 +47,17 @@ jobs:
         tools: phpunit:${{ matrix.phpunit-versions }}
         extensions: pdo_sqlite
 
+    - name: Get composer cache directory
+      id: composer-cache
+      run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+    - name: Cache dependencies
+      uses: actions/cache@v2
+      with:
+        path: ${{ steps.composer-cache.outputs.dir }}
+        key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+        restore-keys: ${{ runner.os }}-composer-
+
     - name: Install Dependencies
       run: composer install --prefer-dist