add the ability to validate a slice of submaps to validate map

[jacobmikesell]

Fixes Or Enhances

Enhances Validate map flow to support nested validation of slices of maps. This comes up when parsing in a json blob like

	b := []byte(`
		{
		    "Name": [
		        {
		            "Role":1234
		        }
		    ]
		}
	`)

with rules that look like

rules := map[string]interface{}{"Name": map[string]interface{}{"Role":"Required"}}

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 increased (+0.1%) to 75.25% when pulling 9be3c32 on apex-fintech-solutions:Add_slice_of_map_support_to_validate_map into ce34f36 on go-playground:master.

[deankarn]

Closing in favour of #917

Both PR's look to achieve the same thing. Please reopen if I am mistaken.