What's Changed
* Update documentation by Bkaribo in https://github.com/DNPLab/DNPLab/pull/481
* Adding method to load s2p vna data by ehuang94 in https://github.com/DNPLab/DNPLab/pull/479
* Change the way to read install require by ehuang94 in https://github.com/DNPLab/DNPLab/pull/478
* Move requirements.txt to docs folder by ehuang94 in https://github.com/DNPLab/DNPLab/pull/483
* Prepare for DNPLab v2.1.20 Release by tkeller12 in https://github.com/DNPLab/DNPLab/pull/482
**Full Changelog**: https://github.com/DNPLab/DNPLab/compare/v2.1.19...v2.1.20