Bugfix: numba jitclass import

This commit fixes a bug which appeared due to the new Numba release. Numba moved jitclass import under the `numba.experimental` from `numba`. As a result it was causing issues during the CI builds and importing elastica modules. In order to solve this we removed the `jitclass` import since it is not used.

elastica/_elastica_numba/_rod/_data_structures.py

@@ -2,7 +2,7 @@
 
 import numpy as np
 import numba
-from numba import njit, jitclass, uint32, float64
+from numba import njit
 from elastica._elastica_numba._rotations import _get_rotation_matrix, _rotate
 from elastica._elastica_numba._linalg import _batch_matmul