fix: conditionally compile ShortBigInt tag. Close #13

Author: Icemic

src/value/tag.rs

@@ -23,6 +23,7 @@ pub enum JsTag {
  Uninitialized = q::JS_TAG_UNINITIALIZED,
  CatchOffset = q::JS_TAG_CATCH_OFFSET,
  Exception = q::JS_TAG_EXCEPTION,
+ #[cfg(feature = "bigint")]
  ShortBigInt = q::JS_TAG_SHORT_BIG_INT,
  Float64 = q::JS_TAG_FLOAT64,
 }