ncu-config: introduce project config file

[mmarchini]

Project config file is intended to be committed to a project. This will
allow other projects in the org to use NCU without users having to set
owner and repo by themselves. In the future we can also use this add
other project-specific configurations (number of hours to wait, minimum
approvals and main CI, for example).

[codecov]

Codecov Report

Merging #364 into master will increase coverage by 0.1%.
The diff coverage is 84.61%.

@@            Coverage Diff            @@
##           master     #364     +/-   ##
=========================================
+ Coverage   75.08%   75.19%   +0.1%     
=========================================
  Files          21       21             
  Lines        1397     1407     +10     
=========================================
+ Hits         1049     1058      +9     
- Misses        348      349      +1

Impacted Files	Coverage Δ
lib/config.js	80.95% <84.61%> (+2.82%)	⬆️

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[priyank-p]

Shouldn't we just rather look for ~/.ncurc by default without having to pass in -g or --global flag? and use that if it exists. And not look for it if -p is passed and rather use ./.ncurc.

(I don't use the tool so can't tell for sure that this is indeed better implementation; this is just a idea from looking at the code)

[mmarchini]

Today ncu-config will look at $PWD/.ncu/config (known as local configs in the source code) if no flags are passed, I didn't want to change this behavior. Also, ncu-config is used only for config manipulation, so it makes sense for the user to explicitly say which config file they want to change/look. Maybe it would make sense for ncu-config list to show configs from all files (like git config does), but I don't think many users use list to make a difference.

All other tools rely on getMergedConfigs, which will fetch configs from all three locations and merge them, prioritizing local config, then project config, then global config.

[joyeecheung]

Why do we need arguments for these? I think we can simply let ./.ncu/config override ./.ncurc which overrides ~/.ncurc?

[mmarchini]

Why do we need arguments for these?

The arguments are only for ncu-config, which is how it worked before (--global to modify ~/.ncurc, no arguments to modify ./.ncu/config). Without the arguments we wouldn't be able to set values (ncu-config set) for a specific file.

I think we can simply let ./.ncu/config override ./.ncurc which overrides ~/.ncurc?

That's the behavior for git-node and other commands, no extra arguments needed.