Add --ignore-paths option

[eFrane]

This can be used to disable the validation on some paths.

Example use case are auto-generated paths in a VuePress site which do not exist as markdown file but may be linked to.

I am not entirely happy with this. Ideally, having a path ignored should - in my opinion - exit out of that links' evaluation. Unfortunately, the only way I see to implement this would be to wrap the whole evaluation step in a try-catch and throw out if ignorePaths.includes(pathname). Instead of doing that, I would much rather untangle the beast the if-chain is becoming. That is a discussion to be had separately (or started here and moved to a separate PR?)

Another thing with change: Things won't work with attached fragments. This goes back to the above issue of the continued evaluation. I'm sure there's a condition in there which can be slightly modified to catch ignored paths with fragments too, but I failed to identify it. 🙁

Anyway, thanks for this awesome tool, it's a huge time saver. ❤️

[codecov-commenter]

Codecov Report

Merging #10 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master      #10   +/-   ##
=======================================
  Coverage   97.89%   97.89%           
=======================================
  Files           2        2           
  Lines         190      190           
=======================================
  Hits          186      186           
  Misses          4        4           

Impacted Files	Coverage Δ
bin.js	93.33% <ø> (ø)
index.js	98.28% <100.00%> (ø)

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[bidoubiwa]

Could you add some tests ? Mostly to understand the usage