Migrate away from deprecated np.float (blakeblackshear#5898)

It is an alias for the python float type, and got deprecated in 1.20 and
was removed in 1.24. The rest of the project already uses float32
(single), so I believe this is also correct here, as opposed to float64
(double).

frigate/motion.py

@@ -20,8 +20,8 @@ def __init__(
  config.frame_height,
  config.frame_height * frame_shape[1] // frame_shape[0],
  )
- self.avg_frame = np.zeros(self.motion_frame_size, np.float)
- self.avg_delta = np.zeros(self.motion_frame_size, np.float)
+ self.avg_frame = np.zeros(self.motion_frame_size, np.float32)
+ self.avg_delta = np.zeros(self.motion_frame_size, np.float32)
  self.motion_frame_count = 0
  self.frame_counter = 0
  resized_mask = cv2.resize(