Signify breaking change in output

[Idane]

Is your feature request related to a problem? Please describe.

When using an exclamation mark to trigger a breaking change, it passes validation. However, the outputs lack an indication that the title represent a breaking change, and even remove the exclamation mark from feat:

feat!: do major release

Outputs:

{
  "type": "feat",
  "scope": "",
  "subject": "do major release"
}

Describe the solution you'd like

Add a breakingChange boolean output

Describe alternatives you've considered

[amannn]

This action uses conventional-commits-parser to parse the PR title and subsequently populates the output:

https://github.com/amannn/action-semantic-pull-request/blob/80c0371c57c5142ed6c844270bba1864bac8a4c6/src/validatePrTitle.js#L31-L34

Currently the parser doesn't return any information of whether it's a breaking change. If this information is available upstream in the parser, we could return it to an output.