feat: customize the names of each flavor

[aalex]

Description As a developer I want to be able to customize the names of each flavor of my app, so that it can fit my requirements and my workflow.

Criteria

• By default, the flavors are: development, staging, production
• I can specify some other names with the --flavors option
• Its value should be a comma-separated string

Example This will create three flavors: free, pro and dev:

very_good create flutter_app my_app --flavors="free,pro,dev"

Additional features Optionally, it could be possible to create another number of flavors. For example: --flavors dev,staging,prod,free would create 4 flavors.

Again optionally, an empty string would disables flavors altogether.

See also

• similar to #476
• related to #482

[Isuru-Nanayakkara]

I second this. This is a really useful tool. Would be great if it had the option to define custom flavors too.

[sagnik-sanyal]

+1 for this feature

[brad007]

+1 for this feature

[Coffiie]

+1