[BUG] Crash due to floating point instead of int

[Edan Toledo]

Describe the bug

The timestep variable $t$ is sometimes a float and other times an int. It depends on the configs.

Super simple fix:

wherever you see :

t = steps_per_rollout * (eval_step + 1)

make it:

t = int(steps_per_rollout * (eval_step + 1))

Expected behavior

A crash not happening.