fix version

Author: hauner

openapi-parser/src/main/java/io/openapiparser/OpenApiVersionParser.java

@@ -19,7 +19,7 @@ public static OpenApiVersion parseVersion(Object document) {
  String version = getVersion(document);
 
  if (isVersion30(version)) {
- return OpenApiVersion.V31;
+ return OpenApiVersion.V30;
 
  } else if (isVersion31(version)) {
  return OpenApiVersion.V31;