Tools/scripts/update-rust-port.sh: script to update Rust-based ports

Hi,


I just added the Tools/scripts/update-rust-port.sh script that automates 
Rust-based port updates.


How to use it:

$ cd /usr/ports/{categ}/{port}

$ ../../Tools/scripts/update-rust-port.sh <new-version>

Then please build it in poudriere and commit it if successful.


I hope that people will find it useful.


Another useful script is Tools/scripts/add-port-to-category-makefile.sh 
- it adds a new port to category Makefile.



Best,

Yuri