message: Fix restore-keys in cache example in README with dependency range
diff: @@ -718,7 +718,7 @@ key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}
  - If you support a range of `composer` dependencies and use `prefer-lowest` and `prefer-stable` options, you can store them in your matrix and add them to the keys.
  ```yaml
  -key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}-${{ matrix.prefer }}-
  +key: ${{ runner.os }}-composer-${{ matrix.prefer }}-${{ hashFiles('**/composer.lock') }}
  restore-keys: ${{ runner.os }}-composer-${{ matrix.prefer }}-
  ```
  