BREAKING CHANGE should not be in the title #16

As the specification of conventional commit says:

BREAKING CHANGE: a commit that has the text BREAKING CHANGE: at the beginning of its optional body or footer section introduces a breaking API change (correlating with MAJOR in semantic versioning). A BREAKING CHANGE can be part of commits of any type.

Suggested implementation

Add new prompt "Is this a BREAKING CHANGE?", which will add to the description in the body the text BREAKING CHANGE: if True

Bump version will only have to modify it's git.get_commits to include the body

git log --pretty=format:%s%b {start}...{end}