Add update-rust-nightly bin script.
Add update-rust-nightly bin script.

* Based on https://github.com/zargony/dotfiles/blob/master/bin/update-rust-nightly

davestephens/dotfiles,tomjrob/dotfiles,edhaker13/dotfiles,ekilmer/dotfiles,CodisRedding/dotfiles,watho/dotfiles,jaredbonobos/dotfiles,edhaker13/dotfiles,watho/dotfiles,brandonjc/dotfiles,jdloft/dotfiles-1,TimeDelta/dotfiles,vabole/dotfiles,c17r/dotfiles,CodisRedding/dotfiles,watho/dotfiles,c17r/dotfiles,Mooash/dotfiles,Jakobo/dotfiles,jaredbonobos/dotfiles,tkruse/dotfiles,KKfo/dotfiles,c17r/dotfiles,cowboy/dotfiles,ricardorsierra/dotfiles,jdwije/dotfiles,Mooash/dotfiles,amxn/dotfiles,hwrod/dotfiles,unicell/dotfiles,mikerathbun/dotfiles,whizzzkid/dotfiles,Tom5om/dotfiles,drzax/dotfiles,ricardorsierra/dotfiles,KKfo/dotfiles,austinrivas/dotfiles,junjizhi/dotfiles-1,wesedens/dotfiles,tomjrob/dotfiles,junjizhi/dotfiles-1,ricardorsierra/dotfiles,hwrod/dotfiles,ekilmer/dotfiles,jdloft/dotfiles-1,edhaker13/dotfiles,porcoesphino/dotfiles,matlockx/dotfiles,porcoesphino/dotfiles,coopermaruyama/dotfiles-cowboy,matlockx/dotfiles,vabole/dotfiles,tuanderful/dotfiles,TimeDelta/dotfiles,edhaker13/dotfiles,tomjrob/dotfiles,Mooash/dotfiles,fkasper/dotfiles,montyubuntu/dotfiles,c17r/dotfiles,fkasper/dotfiles,tuanderful/dotfiles,whizzzkid/dotfiles,whizzzkid/dotfiles,montyubuntu/dotfiles,WillChilds-Klein/dotfiles,unicell/dotfiles,davestephens/dotfiles,coopermaruyama/dotfiles-cowboy,mikerathbun/dotfiles,Tom5om/dotfiles,unicell/dotfiles,austinrivas/dotfiles,WillChilds-Klein/dotfiles,Tom5om/dotfiles,CodisRedding/dotfiles,ichaber/dotfiles,drzax/dotfiles,WillChilds-Klein/dotfiles,granteagon/dotfiles,KKfo/dotfiles,vabole/dotfiles,tomjrob/dotfiles,drzax/dotfiles,granteagon/dotfiles,tuanderful/dotfiles,wesedens/dotfiles,jesperronn/cowboy-dotfiles,montyubuntu/dotfiles,xiphiaz/dotfiles,vabole/dotfiles,whizzzkid/dotfiles,brandonjc/dotfiles,johaned/dotfiles,brandonjc/dotfiles,xiphiaz/dotfiles,Jakobo/dotfiles,fkasper/dotfiles,matlockx/dotfiles,SirBraneDamuj/dotfiles,jesperronn/cowboy-dotfiles,jesperronn/cowboy-dotfiles,ichaber/dotfiles,cowboy/dotfiles,hwrod/dotfiles,viklund/dotfiles,dojoteef/dotfiles,viklund/dotfiles,watho/dotfiles,tkruse/dotfiles,Jakobo/dotfiles,ricardorsierra/dotfiles,porcoesphino/dotfiles,Mooash/dotfiles,TimeDelta/dotfiles,WillChilds-Klein/dotfiles,mikerathbun/dotfiles,tuanderful/dotfiles,TimeDelta/dotfiles,hwrod/dotfiles,coopermaruyama/dotfiles-cowboy,Jakobo/dotfiles,jdloft/dotfiles-1,johaned/dotfiles,xiphiaz/dotfiles,amxn/dotfiles,ifigueroap/dotfiles,davestephens/dotfiles,hwrod/dotfiles,TimeDelta/dotfiles,SteVwonder/dotfiles,johaned/dotfiles,c17r/dotfiles,viklund/dotfiles,amxn/dotfiles,ifigueroap/dotfiles,ekilmer/dotfiles,jaredbonobos/dotfiles,coopermaruyama/dotfiles-cowboy,amxn/dotfiles,brandonjc/dotfiles,davestephens/dotfiles,coopermaruyama/dotfiles-cowboy,SteVwonder/dotfiles,matlockx/dotfiles,granteagon/dotfiles,ichaber/dotfiles,SteVwonder/dotfiles,ifigueroap/dotfiles,Tom5om/dotfiles,SteVwonder/dotfiles,xiphiaz/dotfiles,mikerathbun/dotfiles,jdloft/dotfiles-1,fkasper/dotfiles,junjizhi/dotfiles-1,montyubuntu/dotfiles,junjizhi/dotfiles-1,cowboy/dotfiles,granteagon/dotfiles,hwrod/dotfiles,porcoesphino/dotfiles,TimeDelta/dotfiles,jaredbonobos/dotfiles,unicell/dotfiles,johaned/dotfiles,jesperronn/cowboy-dotfiles,KKfo/dotfiles,ichaber/dotfiles,cowboy/dotfiles,CodisRedding/dotfiles