System information

• TensorFlow version: 2.3.0
• Are you willing to contribute it: Possibly

Describe the feature and the current behavior/state.
tf.math.argmax/argmin does not support ragged tensors.
Will this change the current api? How?
No breaking changes, simply additive in nature.
Who will benefit with this feature?
In my opinion this is particularly important, as it can condense a ragged dimension down to a 1-dimension. In my use case, I have predictions that can be of variable length. I want to take the minimum, which would effectively eliminate the ragged dimension.
Any Other info.
For anyone else looking for a workaround, currently my approach is to convert the ragged tensor to a regular tensor. The default value should be max positive number if you are performing min or max negative number if you are performing max.