[New] Add `--ignore-pattern` flag

[ppati000]

This PR introduces the --ignorePattern flag as a shorthand for ignoring test files.

The flag may be used together with --ignore; the input will be concatenated in that case. I figured this behavior would make the most sense, since users may want to ignore everything in .gitignore and some other files on top.

Let me know if this looks good, then I'll also add some documentation :)

Fixes https://github.com/ljharb/tape/issues/586

[ljharb]

I've rebased this, and renamed the flag to ignore-pattern to more closely match command-line convention.

All that's missing now is documentation.

[codecov[bot]]

Codecov Report

Base: 96.36% // Head: 96.36% // No change to project coverage :thumbsup:

Coverage data is based on head (8c9fe8e) compared to base (e9c9aba). Patch has no changes to coverable lines.

Additional details and impacted files

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[ppati000]

@ljharb cool, thank you 👌 I've added some documentation now, feel free to make any adjustments as needed!