Bump actions/cache from v2.1.4 to v2.1.5

Bumps [actions/cache](https://github.com/actions/cache) from v2.1.4 to v2.1.5.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](https://github.com/actions/cache/compare/v2.1.4...1a9e2138d905efd099035b49d8b7a3888c653ca8)

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 19d5767..85e85c8 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -32,7 +32,7 @@
 
     steps:
     - uses: actions/checkout@v2.3.4
-    - uses: actions/cache@v2.1.4
+    - uses: actions/cache@v2.1.5
       with:
         path: ~/.m2/repository
         key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}