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/ci.yml

@@ -33,7 +33,7 @@ jobs:
         distribution: 'adopt'
         java-version: ${{ matrix.java }}
     - name: Cache Gradle packages
-      uses: actions/cache@v2.1.5
+      uses: actions/cache@v2.1.6
       with:
         path: ~/.gradle/caches
         key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
@@ -61,7 +61,7 @@ jobs:
           distribution: 'adopt'
           java-version: ${{ matrix.java }}
       - name: Cache Gradle packages
-        uses: actions/cache@v2.1.5
+        uses: actions/cache@v2.1.6
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
@@ -95,7 +95,7 @@ jobs:
           distribution: 'adopt'
           java-version: 11
       - name: Cache Gradle packages
-        uses: actions/cache@v2.1.5
+        uses: actions/cache@v2.1.6
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}