feat: Add support for omitting empty and zero values in validation (including nil pointer and empty content of pointer)

[zeewell]

Fixes Or Enhances

Add the omitzero Tag:

• It allows you to ignore the subsequent validations if the value of a field is empty
• If the field is a pointer and the pointer is nil, ignore the subsequent validations
• If the field is a pointer and the pointer is not nil, but the content value of the pointer is zero, the subsequent validations will be ignored

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

[coveralls]

coverage: 74.347% (+0.03%) from 74.318%
when pulling 68a0594 on zeewell:feature/omitzero
into 6c3307e on go-playground:master.

[zeewell]

Fixes #249 #485 #698 #849

[orihomie]

Waiting for this to be merged

[zeewell]

@deankarn This PR's merge has been blocked, can you help take a look at the issue?

[chrislentz]

@deankarn Do you know when this might be merged?

[deankarn]

Sorry @chrislentz been getting some more people to help maintain this package as my time is super limited.

No reason I can see not to merge though.

[zeewell]

Sorry @chrislentz been getting some more people to help maintain this package as my time is super limited.

No reason I can see not to merge though.

@deankarn If possible, I would like to become a maintainer of this package.