[doc] style api error due to multi-dates

[pindge]

need instruction in doc for handling below errors

---------------------------------------------------------------------------
WMSException                              Traceback (most recent call last)
/tmp/ipykernel_172/839274786.py in <module>
     20 from datacube_ows.styles.api import StandaloneStyle, apply_ows_style_cfg, xarray_image_as_png
     21 
---> 22 xr_image = apply_ows_style_cfg(rgb_cfg, data)
     23 png_image = xarray_image_as_png(xr_image)
     24 with open("example1.png", "wb") as fp:

/env/lib/python3.8/site-packages/datacube_ows/styles/api/base.py in apply_ows_style_cfg(cfg, data, loop_over, valid_data_mask)
     96             8 bit signed integer data named red, green, blue and alpha, representing an 24bit RGBA image.
     97     """
---> 98     return apply_ows_style(
     99         StandaloneStyle(cfg),
    100         data,

/env/lib/python3.8/site-packages/datacube_ows/styles/api/base.py in apply_ows_style(style, data, loop_over, valid_data_mask)
     50     """
     51     if loop_over is None:
---> 52         return style.transform_data(
     53                 data,
     54                 style.to_mask(

/env/lib/python3.8/site-packages/datacube_ows/styles/base.py in transform_data(self, data, mask)
    360         """
    361         input_date_count = self.count_dates(data)
--> 362         mdh = self.get_multi_date_handler(input_date_count)
    363         if mdh is None:
    364             img_data = self.transform_single_date_data(data)

/env/lib/python3.8/site-packages/datacube_ows/styles/base.py in get_multi_date_handler(self, count_or_sized_or_ds)
    442         if count in [0, 1]:
    443             return None
--> 444         raise WMSException(f"Style {self.name} does not support requests with {count} dates")
    445 
    446     @classmethod

WMSException: Style stand_alone does not support requests with 2 dates