update v39.4

The gym is the last one to get a revamp, after that I'll add some new stuff until we hit the 400th!
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-Added a smaller version of each gym ball (4 colors)
-Added 2 dumbbell holders with 3 dumbbell combinations
- Added a 2 tiles gym mat (3 colors) and it's horizontal version (3 colors)
- Added 3 modular grey gym mat with different sizes

*Everyone who already bought the asset can get the new stuff for free

See you and happy game-making! :)