Fix default source overriding config file

[bpolge-kr]

Description (What)

Because the source property was being defaulted to [] on the CLI, this code would never allow the config file to override the default value.

src/get-context/get-config/index.ts:81

function getConfigByName(name: keyof Syncpack.Config.Public, defaultValue?: any): unknown {
    if (typeof (fromCli as any)[name] !== 'undefined')
      return (fromCli as Syncpack.Config.Public)[name];
    if (typeof (fromRcFile as any)[name] !== 'undefined')
      return (fromRcFile as Syncpack.Config.Public)[name];
}

Essentially, fromCli is always set, so the fromRcFile is never even looked at.

I think the best way to fix this is to allow getConfig() from that file to return a default value if nothing is set. Not sure if that's the best place to put this, but it at least puts the default where every part of the code will pull it from

Justification (Why)

It would be nice if the documentation about the configuration file actually worked the way it says it will

How Can This Be Tested?

This test was incorrect.
src/get-context/get-config/get-config.spec.ts:156-161

it('uses config value when set', () => {
    const disk = mockDisk();
    disk.readConfigFileSync.mockReturnValue({ source: ['projects/*'] });
    const config = getConfig(disk, {});
    expect(R.getExn(config).source).toEqual(['projects/*']);
  });

const config = getConfig(disk, {}) was an incorrect state.

• In a branch that doesn't have these changes, set it to the correct state const config = getConfig(disk, { source: [] })
  ** You'll see that it throws an error
• Switch to this branch and the error goes away.

[JamieMason]

Thanks @bpolge-kr, I'd been having trouble in this area with some other config values and it looks like I've missed this. I'm away until Sunday but will take a look soon after.