docs(build): Update docs around releasing and fix bug in version updating script

[slim-bean]

No description provided.

[sh0rez]

What about renaming release-prepare to release-finish for now, because it happens after the release?

[rfratto]

LGTM although I'd also like to see documentation for how to include the release binaries (specifically the ARM ones), since I'm not sure how you do it.

[slim-bean]

What about renaming release-prepare to release-finish for now, because it happens after the release?

I think I'd like to leave it for now as I am debating ways to handle our helm chicken and egg problem (which is the only reason we don't run this first)

I am debating one solution: have the release_prepare script create the branch so it can specify a special name which we could use in a branches filter on the helm-test to prevent running the test on this specific branch name

[slim-bean]

LGTM although I'd also like to see documentation for how to include the release binaries (specifically the ARM ones), since I'm not sure how you do it.

This is done automatically by circle CI during the tag build, via make publish