Add support for dependency caching.

- Fork relevant bits from https://github.com/actions/setup-java
- Use Node.js 16
- Adjust packaging
- Update uuid and other dependencies

Closes #11

__tests__/cache/gradle/.gitignore

@@ -0,0 +1,12 @@
+.gradle
+**/build/
+!src/**/build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache