Add `dry-run`, `version` inputs and `release-type` output

[platogabriel]

SUMMARY

Add inputs:

• dry-run in mode:
  • bump: find and increment current version but do not tag
  • validate: check PR labels but do not find current or next version
• version: use this as current version instead of latest tag

Add ouput:

release-type: type of release (one of major, minor, patch)

RELEASE NOTES

Add dry-run and version inputs for wider use-case support

Add inputs:

• dry-run in mode:
  • bump: find and increment current version but do not tag
  • validate: check PR labels but do not find current or next version
• version: use this as current version instead of latest tag

Add ouput:

release-type: type of release (one of major, minor, patch)

Other changes:

• Make repo-token input optional by setting default to github.token context value (which most people use anyway)
• Move from @zeit/ncc to @vercel/ncc since former was deprecated in favor of latter (and wasn't building on my machine)

[jefflinse]

@platogabriel Apologies that I'm just getting to this now. If you could rebase against the latest master I'd be happy to evaluate these features and review.

[platogabriel]

Thanks for your reply, but I'm closing this since I'm no longer using these new features and cannot commit to working them out