conventionalcommits parser should populate the notes prop for commit with '!'

[pvdlg]

The conventionalcommits preset introduced an additional way to signal breaking with a ! after the type/scope.
For every other presets (and conventionalcommits when using the BREAKING CHANGE footer) the parsed object will have some values in commits.notes and that can be used to determine if the commit is a breaking change or not.

I see the case of a ! after type/scope is handled in the write:

conventional-changelog/packages/conventional-changelog-conventionalcommits/writer-opts.js

Line 65 in 63d8cbe

addBangNotes(commit)

I think the addBangNotes should also be called in the parser.

The commit feat!: Some breaking feature currently parses to:

{
  message: 'feat!: Some breaking feature',
  type: 'feat',
  subject: 'Some breaking feature',
  header: 'feat!: Some breaking feature',
  notes: [],
}

but it should be instead parsed as:

{
  message: 'feat!: Some breaking feature',
  type: 'feat',
  subject: 'Some breaking feature',
  header: 'feat!: Some breaking feature',
  notes: [{title: 'BREAKING CHANGE', text: 'Some breaking feature' }],
}

or maybe:

{
  message: 'feat!: Some breaking feature',
  type: 'feat',
  subject: 'Some breaking feature',
  header: 'feat!: Some breaking feature',
  notes: [{text: 'Some breaking feature' }],
}