Bump actions/cache from 2.1.4 to 2.1.6

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.4 to 2.1.6.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](https://github.com/actions/cache/compare/v2.1.4...v2.1.6)

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 688861f..6c137b3 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@v2.1.6
       with:
         path: ~/.m2/repository
         key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}