Function update

src/vuedraggable.js:160–162

(name, value)

    this.footerOffset = footerOffset;
    var attributes = null;
    const update = (name, value) => {
      attributes = buildAttribute(attributes, name, value);
    };
    const attrs = Object.keys(this.$attrs)
      .filter(key => key === "id" || key.startsWith("data-"))
      .reduce((res, key) => {