Support for placeholders for default value in @RequestParam Annotation

[punit-kulal]

Spring Boot supports placeholder values in @ReqestParam annotation defaultValue parameter.
However SwaggerUI does not resolve the configuration value and instead uses the placeholder as a literal string.
This, results in configuration values being exposed to the SwaggerUI.

[bnasslahsen]

@punit-kulal,

This feature will be available for the next release.