Validate openapi3.Schema failed when Schema.Type is empty string

[EmilGeorgiev]

Fist of all thank you for this great library, I really like it. I have one question:

I am using the version 0.123.0 and the Schema's method validate contains this peace of code

kin-openapi/openapi3/schema.go

Line 892 in 9d820c9

case "":

:

schemaType := schema.Type
switch schemaType {
case "":
case TypeBoolean:
case TypeNumber:
...
case TypeInteger:
...
case TypeString:
...
case TypeArray:
...
case TypeObject:
default:
return stack, fmt.Errorf("unsupported 'type' value %q", schemaType)
}

I updated the library to the version 0.127.0 and in the same method this peace of code is a little bit different. The case for the empty string is missing

kin-openapi/openapi3/schema.go

Line 978 in d722646

switch schemaType {

switch schemaType {
case TypeBoolean:
case TypeNumber:
	...
case TypeInteger:
	....
case TypeString:
		      ....
case TypeArray:
	...
case TypeObject:
default:
	return stack, fmt.Errorf("unsupported 'type' value %q", schemaType)
}

Is this intentional or it is a bug?

[AriehSchneier]

It was changed in this PR: #912

[fenollp]

Indeed this change was overlooked and should have been mentioned in the README's breaking changes section.

The change is however correct IMO.

Feel free to reopen if you want to pursue discussion.