Add log levels

[axelniklasson]

Adds support for log levels and migrates existing log calls to use these levels. There are three new options added to the CLI as arguments:

Flag	Output
--quiet	Errors only — ideal for silent CI jobs
(default)	Key results (issues found, release created, etc)
--verbose	Detailed progress (config, shallow-clone fetches)

Related PR for the GitHub action: linear/linear-release-action#10

[linear-code]

LIN-58763 Add log levels to CLI

[RomainCscn]

Wondering if verbose and debug shouldn't be the same? Feels like having 3 log levels might be too much for this? Wdyt?

[axelniklasson]

I considered that at first, but opted to keep it separate since I think that debug sink and some debug data is borderline internal and there is a case to show quite some more info but still hide the proper debug information (hence the addition of verbose). Not a super strong opinion here, so happy to change if you feel that it is too much.

[RomainCscn]

Ok, no strong opinion either, I'm just trying to lean into simplicity when we can.

[axelniklasson]

Totally, also don't want to make it too complicated. Will merge verboseand debug into one, easier to split it down the line than merge it once we have people using it.