Add an option to unzip the archives

[melix]

I was trying to use this action to download several JDKs automatically so that they could be used by Gradle toolchain support. I was actually surprised by 2 things:

1. this action seems independent of SDKMAN! in the sense that it will not use SDKMAN! to download the image, but perform its own installation mechanism based on SDKMAN! metadata. This was confusing since I expected the installed JDKs to be visible via Gradle toolchain support
2. so far so good, I decided to use the ability to pass environment variables pointing to the installation path of JDKs, but then I discovered that this action only downloads a JDK, but doesn't expand it

It would be great to have an option to expand the zip automatically, and expose a variable pointing to the expanded directory.

[eddumelendez]

Hi @melix

Thanks for the report, it was an initial experimentation on this action. I am working on #11 which is actually using sdkman but is not running on windows. I just started this today so maybe a little bit more of research on my side to make it available on all OS.