Bump actions/cache from 2.1.5 to 2.1.6

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.5 to 2.1.6.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.5...v2.1.6)

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

Author: dependabot[bot]

.github/workflows/build.yml

@@ -13,7 +13,7 @@ jobs:
           distribution: 'zulu'
           java-version: 8
       - name: Cache Maven Dependencies
-        uses: actions/cache@v2.1.5
+        uses: actions/cache@v2.1.6
         with:
           path: ~/.m2
           key: ubuntu-latest-m2-${{ hashFiles('**/pom.xml') }}