fix: CLI --src flag glob patterns

[marcelo-souzaf]

Context

Resolves #2001.
A set is created with the resolved paths to avoid multiplicity, but glob expressions can't be used as paths, so the code fails when initializing the Config instance with one such expression.
Previously, Path.resolve was called, so the paths were relative to the current working directory (CWD).

Overview

• Change the type of the config value "src_paths" from pathlib.Path to str.
• Pass the CWD as the "directory" config key to make the paths relative to it instead of the project root.
• Add a test.

[DanielNoord]

This feels like it could do with a small regression test. Do you think you could add one?

[marcelo-souzaf]

I've added one, but I'm not sure if this is the best way to test the CLI behavior.