Make numba.jit an optional requirement.

requirements.txt

@@ -1,4 +1,4 @@
 filterpy==1.4.5
-numba==0.38.1
+numba==0.49.0
 scikit-image==0.14.0
 lap==0.4.0

sort.py

@@ -17,7 +17,6 @@
 """
 from __future__ import print_function
 
-from numba import jit
 import os
 import numpy as np
 import matplotlib
@@ -31,6 +30,12 @@ import time
 import argparse
 from filterpy.kalman import KalmanFilter
 
+try:
+  from numba import jit
+except:
+  def jit(func):
+    return func
+
 np.random.seed(0)