I have already modified 1.12.json like this and put the file into correct folder.

"libraries": [{
"name": "optifine:OptiFine:1.12_HD_U_C5"
},
{
"name": "bboutlinereloaded:BBOutlineReloaded:Vanilla1.12_1.0.0_beta17"
},
{
"name": "net.minecraft:launchwrapper:1.12"
}],

I could lunch the game,but the mod didn't work.When I wanted to edit options-controls, the game crashed.

Reference:This page shows the way to install a mod though launchwrapper.

This works with 1.0.4-beta2 for 1.13, 1.13.1 & 1.13.2. Don't forget to add the tweak class.