update version. remove challenge link
update version. remove challenge link

jpellerin/PhysicsJS,mcanthony/PhysicsJS,Nayar/PhysicsJS,eric-seekas/PhysicsJS,pietro909/PhysicsJS,wellcaffeinated/PhysicsJS,Nayar/PhysicsJS,pietro909/PhysicsJS,aldeed/PhysicsJS,rohit765/PhysicsJS,Rawneed/PhysicsJS,mcanthony/PhysicsJS,haithemaraissia/PhysicsJS,griever989/PhysicsJS,Luwdo/PhysicsJS,haithemaraissia/PhysicsJS,griever989/PhysicsJS,131/PhysicsJS,Rawneed/PhysicsJS,VANITAX/PhysicsJS,jpellerin/PhysicsJS,VANITAX/PhysicsJS,rohit765/PhysicsJS,aldeed/PhysicsJS,Luwdo/PhysicsJS,wellcaffeinated/PhysicsJS,eric-seekas/PhysicsJS