XTB gaussian workaround doesn't work with some versions of XTB

[xiaoruiDong]

See grimme-lab/xtb#773. The fix (added in 2023) is merged but mctc-lib haven't had a new release since Aug 22. This makes newer xtb doesn't support Ein.

XTB version should be <= 6.4.1.
Tested but not working 6.5.0, 6.5.1, 6.6.0, 6.7.0

[xiaoruiDong]

Currently with conda-forge, you cannot install xtb-python with xtb <= 6.4.1 on python >= 3.10. Should install xtb-python with pip, pip install xtb=22.1