Add "sources" config key

[f-f]

Spago includes some default path globs in the build:

• src/**/*.purs
• test/**/*.purs

However, if you don't have those directories, it will complain:

purs compile: No files found using pattern: src/**/*.purs
purs compile: No files found using pattern: test/**/*.purs

I propose we instead make this explicit (and configurable) by adding a sources (or paths) key to the configuration, and removing the implicit paths.
We should migrate existing configurations so the change is backwards compatible.

[jmackie]

+1

[f-f]

Related to this: I just discovered that purs build --watch doesn't work if you are missing one of the defaults folders.

I'll add a "bug" label because I think the fix for this issue should also address it.

[bbarker]

Perhaps this can also be disabled somehow, since in the case where one's tests has additional dependencies, it should be structured as a separate project described in https://github.com/spacchetti/spago/#separate-devdependencies-or-test-dependencies ?

[f-f]

@bbarker Once we enable this you'd explicitly have the globs in your spago.dhall, e.g. for a test-only project:

{ name = "my-tests"
, packages = ../packages.dhall
, dependencies = [ "console", "effect", "prelude" ]
, sources = [ "test/**/*.purs" ]
}