black 21.12b0 on Python PyPI

Fix determination of f-string expression spans (#2654)
Fix bad formatting of error messages about EOF in multi-line statements (#2343)
Functions and classes in blocks now have more consistent surrounding spacing (#2472)

Cell magics are now only processed if they are known Python cell magics. Earlier, all cell magics were tokenized, leading to possible indentation errors e.g. with %%writefile. (#2630)
Fix assignment to environment variables in Jupyter Notebooks (#2642)

Point users to using --target-version py310 if we detect 3.10-only syntax (#2668)
Fix match statements with open sequence subjects, like match a, b: or match a, *b: (#2639) (#2659)
Fix match/case statements that contain match/case soft keywords multiple times, like match re.match() (#2661)
Fix case statements with an inline body (#2665)
Fix styling of starred expressions inside match subject (#2667)
Fix parser error location on invalid syntax in a match statement (#2649)
Fix Python 3.10 support on platforms without ProcessPoolExecutor (#2631)
Improve parsing performance on code that uses match under --target-version py310 up to ~50% (#2670)

@isidentical for the polishing up 3.10 syntax support (which they contributed in the first place!)
@MarcoGorelli for their ever-continuing work on Black's jupyter support
@jalaziz for cleaning up our Pyinstaller CD workflow
@hauntsaninja for helping us drop the regex dependency

And also congrats to first contributors!