Minor issue due to mismatch of data types in transform3d.py

[kidpaul94]

In line 749 of transform3d.py,

pytorch_kinematics/src/pytorch_kinematics/transforms/transform3d.py

Line 749 in a457cda

return a.bmm(b)

It keeps causing an error when I try to visualize sdf using pv.draw_sdf_slice because a is a float tensor while b is a double tensor.

Just a heads up since I'm not sure how critical this is when using other functions in pytorch_kinematics.

I faced this issue when I tried to specify dtype of a chain class.