packaging: normalize - to _ in WiX Id values
- is not a valid identifier character in WiX Ids. So let's
normalize accordingly.
I discovered this issue after a subsequent change which introduces
a directory with a - in its name.
Differential Revision: https://phab.mercurial-scm.org/D9147
contrib: install Rust 1.46.0
Let's use the latest/greatest version of Rust in the automation
environment.
Differential Revision: https://phab.mercurial-scm.org/D9146
contrib: install latest versions of Python
Let's keep our build environment modern.
We upgrade 3.5-3.8 on Linux. Just 3.7 and 3.8 on Windows because we
don't use <3.7 on Windows.
Differential Revision: https://phab.mercurial-scm.org/D9145