os/mac/pkgconfig: merge pc files for 11.1 and 11.0

[carlocab]

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Closes #10126.

This combines the pc files for Big Sur 11.0 and 11.1. We no longer distinguish between minor versions of Big Sur in the CLT since #10072.

Merge this before #10150.

[BrewTestBot]

Review period will end on 2020-12-25 at 07:35:58 UTC.

[MikeMcQuaid]

Thanks for this @carlocab!

[BrewTestBot]

Review period ended.

[MikeMcQuaid]

Thanks @carlocab!

[carlocab]

No, thank you, @MikeMcQuaid. I've been a Homebrew user for such a long time it's a little shocking how long it took me to start contributing.

[MikeMcQuaid]

Thanks again @carlocab!