Make docs for required more explicit regarding boolean values

[alexongh]

required validates that the value is not the data types default zero value. For boolean the default zero value is false. Therefore, a false boolean value would be interpreted as not matching the required validation and fail.

This, in my opinion, is a little unexpected. Judging from the name required only, I expected that a false boolean value would be ok, since a value was provided.

Nevertheless, in my opinion, this behavior should be documented a little more explicitly. Which is why I propose this change to the docs.

• [x] Tests exist or have been written that cover this particular change. (this is only a docs change)

@go-playground/validator-maintainers

[coveralls]

coverage: 74.243%. remained the same when pulling 043e9ee10186ea374ef9b82d45419cdee8a8a5ee on alexongh:master into e20b94842ab102ba94e73eaf66f5c0466e405882 on go-playground:master.

[JackFeng7]

This, in my opinion, is a little unexpected. Judging from the name required only, I expected that a false boolean value would be ok, since a value was provided.

Can we recover the literal meaning of required instead of being kidnapped by go's zero value ？