Dpgui

The first stable version of DP-GUI v1.

What's Changed
* add importlib_metadata to dependencies for Python 3.7 by njzjz in https://github.com/deepmodeling/dpgui/pull/272


**Full Changelog**: https://github.com/deepmodeling/dpgui/compare/v1.0.0-rc1...v1.0.0-rc2

What's Changed
* change Python build output directory by njzjz in https://github.com/deepmodeling/dpgui/pull/271


**Full Changelog**: https://github.com/deepmodeling/dpgui/compare/v1.0.0-rc0...v1.0.0-rc1

This is the first version of the independent Python package. The support for switching the language between English and Chinese is also added.