Image normalisation does not work with grey scale images.

[jacekpie]

I connected grey-scale image source to image normalisation module.
The output from image source is
u8[1, 31, 200, 1]

Image normalisation logs out an error: "the number of channels should be either 1 or 3, found 1"

[Michael-F-Bryan]

The code at fault is this match statement:

proc-blocks/image-normalization/src/lib.rs

Lines 22 to 29 in 46fae77

	match *dimensions {
	[_, _, _, 3] => {},
	[_, _, _, channels] => panic!(
	"The number of channels should be either 1 or 3, found {}",
	channels
	),
	_ => panic!("The image normalization proc block only supports outputs of the form [frames, rows, columns, channels], found {:?}", dimensions),
	}

The first arm needs to be changed to [_, _, _, 3] | [_, _, _, 1] => {} when we go through and migrate the image-normalization proc-block to the new Rune ABI.