Package Lecture Link

[arnavs]

Andrew shared his blog post with me: https://aaowens.github.io/2020/01/13/A-Newcomers-Guide-to-the-Julia-Package-Manager.html

Add it to the package lecture sometime.

Also maybe the project!"foo" and manifest!"foo" features from PkgUtils. Copy/pasting those files into a script so they can be run anywhere.