Bump actions/cache from 2.1.5 to 2.1.6 (#35)

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] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -24,7 +24,7 @@ jobs:
           java-version: ${{ matrix.java }}
           architecture: ${{ matrix.architecture }}
 
-      - uses: actions/[email protected].5
+      - uses: actions/[email protected].6
         with:
           path: ~/.m2/repository
           key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}