add announcement for moving to macOS 11

[h-vetinari]

For #2467, modelled after #1993

Draft for discussion

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[h-vetinari]

@jakirkham, this is the announcement you were asking for

[jakirkham]

Thanks Axel! 🙏

This looks reasonable

Had a few questions below

[h-vetinari]

Any further comments here? Otherwise I'll merge this in 24h.

[jakirkham]

Looks great! Thanks Axel 🙏

[jakirkham]

Link check is failing. Checked all the links manually. Maybe it is just being flaky? This wouldn't be the first time

[h-vetinari]

Link check is failing. Checked all the links manually. Maybe it is just being flaky? This wouldn't be the first time

Yeah, there have been persistent issues with this recently. We should IMO introduce an ignorelist for the link check (though I'm not very deep in the website setup here, so not sure how easily that's possible). CC @jaimergp

[h-vetinari]

Thanks for the review!