No error checking on git commands

[pianohacker]

While using linear issue start, I noticed that git errors are currently swallowed. My thought would be to add a wrapper with error checking in places like https://github.com/schpet/linear-cli/blob/main/src/utils/actions.ts#L117-L120 where we're currently calling git unchecked.

Any concerns or preferences as to how to implement this?

[schpet]

@pianohacker oh! good catch. yeah whatever you think makes sense. i'd be satisfied with just simply throwing something with a reasonable message, but if you want to do something more comprehensive i'm not opposed