Improve documentation on how to bump a major version

[eedzjee]

I was trying to bump a project's major version from 0.1.0 to 1.0.0, using the exclamation mark in the commit message:

feat!: this is a breaking change

Generating the changelog, it does add this beneath the heading "Breaking Changes", but the version only bumped to 0.2.0. After investigating this further, I found the comment in the code that says never to bump a the major version in a development release: https://github.com/qoomon/git-conventional-commits/blob/master/lib/semver.js#L4

I couldn't find anything about this in the README of this project. It might be a good idea to describe:

• How to bump a major version (using the exclamation mark !)
• Why it doesn't apply for development releases 0.x.x
• And how to bump a development release to 1.0.0 (should this be done manually then?)

[qoomon]

And how to bump a development release to 1.0.0 (should this be done manually then?)

yes

[qoomon]

@eedzjee would you be so kind and create a tiny PR for this documentation improvement.

[eedzjee]

@qoomon I can do that. I'll see if I can find the time this week.

[eedzjee]

@qoomon It was a smaller task than anticipated, so the PR is ready for review. I also took the liberty to review the full README.md and made some changes regarding grammar, spelling and other undocumented behaviour.

Next to that: I've updated the Cheatsheet Gist: https://gist.github.com/eedzjee/39f50ff34866cd2bae7861eba148e0b1 with a proposal in this fork: https://gist.github.com/eedzjee/39f50ff34866cd2bae7861eba148e0b1

I cannot submit a PR for that, but you could take over the changes I made if you agree with them.