Implement negative matching for files in outputs

[duncanmmacleod]

This PR implements #4196 by adding supporting for a negative match expression for the files list in outputs.

Closes #4196.

[duncanmmacleod]

@mingwandroid, I think this is ready for a review (sorry if there's a better @ ping for the conda-build team). The macOS jobs are failing, but the logs suggest it's not my fault..

[duncanmmacleod]

Ping for anyone to review this.

[mbargull]

Needs to consider filenames starting with !.

[mbargull]

We also need to consider files which themselves start with a !. For example with gitignore you can start entries with \! for this.
Personally, I'd rather suggest to have a more explicit form to avoid these custom syntax and special cases (also wrt. YAML tags). I.e., I'd rather have files optionally be a dictionary with two keys:

  files:
    include:
      - *.txt
    exclude:
      - do-not-want.txt

.

[jezdez]

Agreed, @mbargull!

[jezdez]

I concur with @mbargull's comment, this should be done with a new exclude section instead of prepending the filename with !.

[github-actions]

Hi there, thank you for your contribution!

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Thanks!