First, if you want a resource pack that has the new colored beds, please feel free to check out either of my resource packs. The links are in my signature. They are 1.12.2 ready and yes, they have the beds.
But if you still want to know where in a pack they are the answer is that they're in the entity folder. In particular "/assets/minecraft/textures/entity/bed/". The file names are just the color name, with the exception of "light gray" which is "silver.png". Do note that "light_blue.png" is done with an underscore as well, being the only two-word color name. (Why they didn't go with "sky" is beyond me.)
I hope that helps you!
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For any version of the mod, it's like the config options are locked, and i cant use the mod