class_docstr: Converts a color image observation specified using the RGB encoding into a grayscale
  image observation, by keeping only the luminance (Y) channel of the YUV encoding. This can be useful if the colors
  in the original image are not relevant for solving the task at hand.
  The channels axis is assumed to be the last axis
code: def __init__(self):
      super().__init__()
  
file_path: coach/rl_coach/filters/observation/observation_rgb_to_y_filter.py
imports: from rl_coach.core_types import ObservationType
  from rl_coach.filters.observation.observation_filter import ObservationFilter
  from rl_coach.spaces import ObservationSpace
label_desc: Use image node_id 1 to create a new ObservationRGBToYFilter object from inherited base classes: ObservationFilter with example: obj = ObservationRGBToYFilter()