handle generic wildcard parameter

Author: hauner

src/main/kotlin/io/openapiprocessor/core/model/datatypes/MappedDataType.kt

@@ -44,7 +44,7 @@ open class MappedDataType(
     }
 
     override fun getImports(): Set<String> {
-        return setOf("${getPackageName()}.$type") + genericTypes
+        return setOf("${getPackageName()}.$type") + genericTypes.filter { it != "?" }
     }
 
     private fun getGenericTypeNames(): List<String> {

src/test/groovy/com/github/hauner/openapi/core/model/datatypes/MappedDataTypeSpec.groovy

@@ -32,6 +32,7 @@ class MappedDataTypeSpec extends Specification {
         where:
         generics                                 | typeName
         []                                       | 'Foo'
+        ['?']                                    | 'Foo<?>'
         ['java.lang.String']                     | 'Foo<String>'
         ['java.lang.String', 'java.lang.String'] | 'Foo<String, String>'
     }
@@ -46,6 +47,7 @@ class MappedDataTypeSpec extends Specification {
         where:
         generics                                 | imports
         []                                       | ['model.Foo']
+        ['?']                                    | ['model.Foo']
         ['java.lang.String']                     | ['model.Foo', 'java.lang.String']
         ['java.lang.String', 'java.lang.String'] | ['model.Foo', 'java.lang.String']
     }