Bump actions/cache from 2.1.4 to 2.1.5

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.4 to 2.1.5.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.4...v2.1.5)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -68,15 +68,15 @@ jobs:
                     echo "::set-output name=dir::$(composer config cache-files-dir)"
 
             -   name: Cache Composer Downloads
-                uses: actions/cache@v2.1.4
+                uses: actions/cache@v2.1.5
                 with:
                     path: vendor/
                     key: ${{ runner.os }}-${{ matrix.php }}-composer-${{ hashFiles('**/composer.lock') }}
                     restore-keys: |
                         ${{ runner.os }}-${{ matrix.php }}-composer-${{ hashFiles('**/composer.lock') }}
                 
             -   name: Cache PHP dependencies
-                uses: actions/cache@v2.1.4
+                uses: actions/cache@v2.1.5
                 with:
                     path: vendor
                     key: ${{ runner.os }}-${{ matrix.php }}-composer-${{ hashFiles('**/composer.lock') }}