Add cache action to Maven workflow (#3013)
Add cache action to Maven workflow (#3013)

* Add cache action to Maven workflow
  * https://help.github.com/en/github/automating-your-workflow-with-github-actions/caching-dependencies-to-speed-up-workflows
  * https://github.com/actions/cache/blob/e1ed41a9c913f73dd08e261583c25e9d5eca5007/examples.md#java---maven

* Use OS-specific cache steps

Refs actions/cache#39
micsta/dropwizard,Alexey1Gavrilov/dropwizard,mosoft521/dropwizard,pkwarren/dropwizard,dropwizard/dropwizard,mosoft521/dropwizard,Alexey1Gavrilov/dropwizard,pkwarren/dropwizard,phambryan/dropwizard,dropwizard/dropwizard,micsta/dropwizard,phambryan/dropwizard,phambryan/dropwizard,dropwizard/dropwizard,micsta/dropwizard,pkwarren/dropwizard,Alexey1Gavrilov/dropwizard,mosoft521/dropwizard