Migrate away from deprecated np.float

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(