Allow setting a release as a draft

[ShonP40]

Useful in case you want to prepare a release but only publish it at a later date or make changes to the title/description

[edgarrmondragon]

Does this makes sense here? This action is used to push files to a release, not creating the release itself. For that, there's https://github.com/softprops/action-gh-release for example, and it does support creating a release as draft.

[ShonP40]

This action does create a release if one doesn't already exist though

[williamdes]

Thank you!