automation: refresh requirements
I'm hitting errors installing the old version of cffi due to an
apparent issue where older versions of cffi aren't compatible with
the modern Clang I'm using. So let's upgrade packages to unbreak
things and to keep things modern.
Differential Revision: https://phab.mercurial-scm.org/D12629
Hello, Foobar
[b'Hello, Fo, =;:<o', b'Hello, Bar']