pandas更新之后dataframe没有append了

[ohmyboy12]

pandas更新之后dataframe没有append了，universal.py的第2029行，作者有空可以修改一下，
df0 = pd.concat([df0,df2],ignore_index=True, sort=False)。
加油~

[refraction-ray]

possible related issue: #171, will have a look

[refraction-ray]

currently the fix is in a new branch: https://github.com/refraction-ray/xalpha/tree/pd2, since pandas 2.0 has made verious breaking changes, the overall effect remains to be checked due to limited time. My suggestion is to use pandas version less than 2.0