Support package names shorter than 3 characters

[rebornplusplus]

Chisel does not currently support package names shorter than 3 characters. This is controlled by a few regular expressions specified in the setup package.

chisel/internal/setup/setup.go

Lines 245 to 247 in 11a324c

	var fnameExp = regexp.MustCompile(`^([a-z0-9](?:-?[.a-z0-9+]){2,})\.yaml$`)
	var snameExp = regexp.MustCompile(`^([a-z](?:-?[a-z0-9]){2,})$`)
	var knameExp = regexp.MustCompile(`^([a-z0-9](?:-?[.a-z0-9+]){2,})_([a-z](?:-?[a-z0-9]){2,})$`)

However, this means that packages like jq are not currently supported. Per the debian policy, the minimum length of a package's name can be 2.

Package names (both source and binary, see Package) must consist only of lower case letters (a-z), digits (0-9), plus (+) and minus (-) signs, and periods (.). They must be at least two characters long and must start with an alphanumeric character.

Related: canonical/chisel-releases#116

[cjdcordeiro]

unless you see an obvious rationale for keeping that limitation, I'd propose simply putting a PR up for adjusting that limit (unless it's not straightforward)

[rebornplusplus]

Yeah, this should be a very easy fix. I will add a PR for it shortly. I wanted to add the "Good first issue" label to this issue in case anyone wanted to try it out, but I can't. 😕