Qapprox 0.2.1

• New maintainer: Zheyang Wu (zheyangwu@wpi.edu).
• Authors@R now lists all three authors of the underlying paper (Hong Zhang, Judong Shen, and Zheyang Wu).
• The package now has a public repository and issue tracker: https://github.com/ZWuLab/Qapprox. Added URL and BugReports fields.
• The reference in Description now points to the published paper (Zhang, Shen and Wu, 2022, Journal of Computational and Graphical Statistics, doi:10.1080/10618600.2021.2000423) instead of the arXiv preprint.
• No changes to functions or computations.