I hate to be that one guy; however, @Jinyu Meng's solution is not viable. While it does let us use the "FUNCTION" key as our sprint, it makes us have to reconfigure our Dual-Wielding key. Along with that, in most scenarios, we'll have to use both hands in order to toggle our #F-keys rather than 1 as before. Using this solution also prevents us from typing the letter "F" in chat, making this extremely annoying on multiplayer as well as when you're doing command work. Lastly, using Karabiner effects ALL versions of the game, not just the 1.13 Pre-releases; moreover, making this a temporary but not great work-around
Really hoping this is fixed before the final release!
Cole Smith 
MC-133231
Yes, I run Mac OSX
I hate to be that one guy; however, @Jinyu Meng's solution is not viable. While it does let us use the "FUNCTION" key as our sprint, it makes us have to reconfigure our Dual-Wielding key. Along with that, in most scenarios, we'll have to use both hands in order to toggle our #F-keys rather than 1 as before. Using this solution also prevents us from typing the letter "F" in chat, making this extremely annoying on multiplayer as well as when you're doing command work. Lastly, using Karabiner effects ALL versions of the game, not just the 1.13 Pre-releases; moreover, making this a temporary but not great work-around
Really hoping this is fixed before the final release!