Allow BindStyledParameterWithOptions to fill maps

[JoZie]

In our API we have something like:

/v2/store/{key}:
put:
summary: Store with Metadataparameters:
- name: keyin: pathrequired: trueexplode: falsestyle: simpleschema:
type: string
- name: X-Metadatain: headerrequired: falseexplode: falseschema:
type: objectadditionalProperties:
type: string

If the X-Metadata header is defined with e.g. "foo,bar" I always get the error:Invalid format for parameter X-Metadata: error binding string parameter: can not bind to destination of type: map.

The issue is that the X-Metadata type is a map[string]string which is not handled by BindStyledParameterWithOptions.

I extended the function to use the same code path for reflect.Map as for reflect.Struct