Permit rc versions when using gleam add

[hayleigh-dot-dev]

When attempting to specify an rc version while adding a package, Gleam reports the following error:

› gleam add lustre_ui@1.0.0-rc.1
error: Invalid version format

I was unable to parse the version "1.0.0-rc.1".
The error from the parser was:

    Expected up to 3 numbers in version specifier (MAJOR.MINOR.PATCH), found 4

This is unfortunately correct, as per the semver spec:

A pre-release version MAY be denoted by appending a hyphen and a series of dot separated identifiers immediately following the patch version. Identifiers MUST comprise only ASCII alphanumerics and hyphens [0-9A-Za-z-].

They also list some valid examples:

• 1.0.0-alpha
• 1.0.0-alpha.1
• 1.0.0-0.3.7
• 1.0.0-x.7.z.92
• 1.0.0-x-y-z.--.

It'd be great if Gleam understood how to add all valid version identifiers so we don't have to dip into editing gleam.toml!

[lpil]

Sounds reasonable. What constraint would it add to gleam.toml?

[hayleigh-dot-dev]

Whenever someone specifies a full version MAJOR.MINOR.PATCH with or without the prelease version I'd expect the gleam.toml to produce an exact constraint.

[lpil]

That's not what it does and we will not be changing it to do that.