Merge pull request #579 from swagger-api/ignore_import_mapping_method

add method to ignore import mapping for a specific generator.

Author: HugoMario

src/main/java/io/swagger/codegen/v3/generators/DefaultCodegenConfig.java

@@ -4240,4 +4240,8 @@ public boolean needsUnflattenedSpec() {
     public void setUnflattenedOpenAPI(OpenAPI unflattenedOpenAPI) {
         this.unflattenedOpenAPI = unflattenedOpenAPI;
     }
+
+    public boolean ignoreImportMapping() {
+        return false;
+    }
 }