Remove `shape_out` as an explicit kwarg from `reproject_to`

[wtbarnes]

Provide a general description of the issue or problem.

The reproject_to method explicitly has a shape_out keyword argument. Previously, the reason for this was because the shape_out needed to potentially be manually extracted from the low-level WCS:

ndcube/ndcube/ndcube.py

Lines 759 to 766 in 64b5f99

	# TODO: Upstream this check into reproject
	# If shape_out is not specified explicitly,
	# try to extract it from the low level WCS
	if not shape_out:
	if hasattr(low_level_target_wcs, 'array_shape') and low_level_target_wcs.array_shape is not None:
	shape_out = low_level_target_wcs.array_shape
	else:
	raise ValueError("shape_out must be specified if target_wcs does not have the array_shape attribute.")

However, this logic is now included in reproject_to as of v0.11.1. Currently, due to the minimum version policy, we need to continue support versions older than v0.11.1. Once that period has passed, shape_out can be removed as an explicit keyword argument and the above logic can be removed.