build(deps): bump actions/cache from v1 to v2.1.1 (OpenAPITools#162)

Bumps [actions/cache](https://github.com/actions/cache) from v1 to v2.1.1.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v1...5ca27f2)

Signed-off-by: dependabot[bot] <[email protected]>

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

Author: dependabot[bot]

.github/workflows/maven.yml

@@ -21,7 +21,7 @@ jobs:
       uses: joschi/setup-jdk@v1
       with:
         java-version: ${{ matrix.java_version }}
-    - uses: actions/cache@v1
+    - uses: actions/cache@v2.1.1
       with:
         path: ~/.m2/repository
         key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}