Omitzero does not work with slice and map bug

[JunaidIslam2105]

Fixes

Fixed a bug where using omitzero still validated empty structs and maps. This PR ensures that if omitzero is used as a tag then empty slices and maps are not validated.

• Modified the baked_in.go file to ensure that slices and maps are considered non zero only when they are not nil and they are not empty.
• Added tests to ensure empty slices and maps are not validated while using omitzero tag.

Check #1424 for more details.

Make sure that you've checked the boxes below before you submit PR:

• Tests exist or have been written that cover this particular change.

@go-playground/validator-maintainers

[JunaidIslam2105]

Hi @nodivbyzero would you kindly take a look if you get some time? Thanks

[coveralls]

coverage: 73.678% (+0.004%) from 73.674%
when pulling dbe3522 on JunaidIslam2105:omitzero-slice-map-bug
into dfc7ccd on go-playground:master.

[nodivbyzero]

This looks good to me.
Thank you for making those changes.

[JunaidIslam2105]

Thanks @nodivbyzero for the review. Can we merge this PR if everything looks good? Also can we work on closing issues #1424 and #1430 ?