change call method to setter

Author: huisam

springdoc-openapi-starter-common/src/main/java/org/springdoc/core/customizers/SpecPropertiesCustomizer.java

@@ -170,7 +170,7 @@ private void customizeExternalDocs(OpenAPI openApi, ExternalDocumentation extern
 			resolveString(externalDocumentation::description, externalDocumentationProperties::getDescription);
 			resolveString(externalDocumentation::url, externalDocumentationProperties::getUrl);
 		} else {
-			openApi.externalDocs(externalDocumentationProperties);
+			openApi.setExternalDocs(externalDocumentationProperties);
 		}
 	}