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