heptapod-ci: enable pytype checking
The trigger is manual for now, until we get a better idea about stability,
resource usage, etc.
Differential Revision: https://phab.mercurial-scm.org/D10462
Matt Harbison <matt_harbison@yahoo.com> [Thu, 06 May 2021 18:40:23 -0400] rev 47039
hghave: fix the definition of `python3` to work on Windows
Both py2 and py3 executables are named `python.exe`, and may or may not be on
PATH. So use the dispatcher executable that comes with py3 to fetch the version
of the latest py3 executable. This allows at least one relnotes test to run on
Windows.
Differential Revision: https://phab.mercurial-scm.org/D10694