ENH: Use NumPy's Generator class as a replacement for RandomState

Use NumPy's `Generator` class as a replacement for `RandomState` for
random variarte generation methods.

Documentation:
https://numpy.org/doc/stable/reference/random/generated/numpy.random.seed.html

src/eddymotion/estimator.py

@@ -87,7 +87,7 @@ def fit(
         align_kwargs = align_kwargs or {}
 
         if seed or seed == 0:
-            np.random.seed(20210324 if seed is True else seed)
+            np.random.default_rng(20210324 if seed is True else seed)
 
         if "num_threads" not in align_kwargs and omp_nthreads is not None:
             align_kwargs["num_threads"] = omp_nthreads