That is simple open the link
https://libraries.minecraft.net/net/sf/jopt-simple/jopt-simple/4.5/jopt-simple-4.5.jar
it will download the file and from there you copy it to C:\Users\(me)\Twitch\Minecraft\Install\libraries\net\sf\jopt-simple\jopt-simple\4.5\jopt-simple-4.5.jar and replace it
