[CodeCamp #2] Add jax support to MeanIoU

[xuan07472]

Motivation

Add jax support to MeanIoU

Modification

Calculated using jax.numpy.ndarray for MeanIoU support, supplemented and unit tested

[CLAassistant]

All committers have signed the CLA.

[ice-tong]

Please update the docstring of MeanIoU~

mmeval/mmeval/metrics/mean_iou.py

Lines 32 to 34 in 25a63aa

	This metric supports 5 kinds of inputs, i.e. ``numpy.ndarray``,
	``torch.Tensor``, ``oneflow.Tensor``, ``tensorflow.Tensor`` and
	``paddle.Tensor``, and the implementation for the calculation depends

[ice-tong]

LGTM, and please @zhouzaida have a look~