fix(readme): Update readme file

[alexfornuto]

Updates readme to include git as a dependency, and match the current release.

[armory-jenkins]

The title of this Pull Request needs to be changed to match the format:

<type>(<scope>): <subject>

See more details here: https://www.spinnaker.io/community/contributing/submitting/#commit-message-conventions

Some common examples are:

feat(armory.io): add docs.armory.io
fix(parser): grammar and spelling
style(loadingPage): made it super pretty!
refactor(helpMessages): changed order to make more sense