Add more command hooks

[webpro]

Also see #34 and #35.

[webpro]

@shimikano, I've added some command hooks. I would appreciate your feedback!

I've actually needed more hooks myself for https://medium.com/@webprolific/using-github-pages-the-easy-way-bb7acc46f45b, so that helped :-)

[shimikano]

Excellent!

I can confirm that beforeStageCommand covers our use case of wanting to keep the version in our pom.xml in sync with the primary json version file.

Moreover, we use beforeStartCommand to have our tests run again before a release.

Thank you for your work, release-it proved to be a nicely customizable tool (and replacement for npm version) for us.

[webpro]

Thanks a lot for your feedback, appreciate it!