Remove or update dependencies to resolve security issues

[jasonaowen]

Resolve several security issues by either updating or removing our dependencies.

In particular:

• remove cz-conventional-changelog
• remove standard-version
• remove open-cli
• update ava
• update ansi-regex

I opted for removal over updating when possible because I don't think we're really making use of the functionality those dependencies bring us, and in particular not to the degree that they require maintenance, but happy to hear otherwise!

[jasonaowen]

It is worth noting, I think, that all of these are dev dependencies and not prod dependencies; this should have zero impact on clients of the SDK.