contrib: rust: force the 1.46.0 version

Rust 1.47.0 is using some forbidden API's in UWP: https://code.videolan.org/videolan/vlc/-/jobs/462281

• https://docs.microsoft.com/en-us/windows/win32/api/tlhelp32/nf-tlhelp32-createtoolhelp32snapshot
• https://docs.microsoft.com/en-us/windows/win32/api/tlhelp32/nf-tlhelp32-module32firstw
• https://docs.microsoft.com/en-us/windows/win32/api/tlhelp32/nf-tlhelp32-module32nextw