Mercurial 4.1-rc tagged

[Augie Fackler]

Please update your package builds, thanks.
Note that this is the first release which includes a vendored zstandard and zstandard-python. If you'd rather not distribute our bundled versions of those libraries, _please_ omit zstandard support from your packaged Mercurial - it'll always be optional, and at present Mercurial requires some unstable APIs from zstandard to function correctly. If you need any guidance on this front, please don't hesitate to ask us here or on mercurial-devel at .

Thanks!