[Feature Request] Automatically install required version or use it

[Islam-alshiki]

Describe the solution you'd like
I would like to propose the addition of a new command that automatically checks the Flutter version required by the app itself and installs it if it does not exist.

Describe alternatives you've considered
FVM need to manually check the required Flutter version, install it

[digoreis]

This feature will be great to migrate the initialised project without fvm. A command setup is a good name ?

fvm setup

And this import recovery the version from pubspec.yml.

[VojtaStanek]

I would appreciate if fvm supported "zero-config setup," automatically reading the Flutter version from pubspec.yml rather than .fvmrc. For straightforward use cases, .fvmrc seems necessary solely for specifying the Flutter version, which is already present in pubspec.yml.

[digoreis]

In this case, the most simple solution is install command has a fallback behaviour to use the Pubspec version parameter how the default version .