update np.float to np.float64

[ElkanaBaris]

numpy >= 1.20 doesn't support dtype=np.float, this causes failure when running metrics.py
I updated all np.float to np.float64

  File "/opt/anaconda3/envs/recbole/lib/python3.9/site-packages/recbole/evaluator/metrics.py", line 190, in metric_info
    iranks = np.zeros_like(pos_index, dtype=np.float)
  File "/opt/anaconda3/envs/recbole/lib/python3.9/site-packages/numpy/__init__.py", line 305, in __getattr__
    raise AttributeError(__former_attrs__[attr])
AttributeError: module 'numpy' has no attribute 'float'.
`np.float` was a deprecated alias for the builtin `float`. To avoid this error in existing code, use `float` by itself. Doing this will not modify any behavior and is safe. If you specifically wanted the numpy scalar type, use `np.float64` here.
The aliases was originally deprecated in NumPy 1.20; for more details and guidance see the original release note at:
    https://numpy.org/devdocs/release/1.20.0-notes.html#deprecations

[zhengbw0324]

Hi @ElkanaBaris, thank you for your attention. In github, we have fix this issue in #1621.