Support for multiple values under the same query parameter name

[andreyfilyakov]

Is your feature request related to a problem? Please describe. In our project we have some requests which require multiple values for the same parameter name, e.g. <base_url>?param=value1&param=value2&param=value3. We tried to use QueryMap annotation to achieve our goal, but it works with Map<String, String> only, so it's not possible to set multiple values for the same key.

Describe the solution you'd like It'd be ideal to support Map<String, List<String>> for QueryMap annotation.