When attempting to install the IAP package, my project crashes and every time i try to open the project afterwards it will crash again and again.

To repro this issue:
1. start a new project
2. add IAP package from Package Manager
2. go to the services window and enable services
3. enable IAP
4. Import the package
5. After import, you will get prompted to INSTALL the package
6. Afterwards you will get a (Asset Store Like) Package Import dialogue
8. Afterwards, you will get and API upgrader dialogue
9. After confirming the API Upgrade, Unity will crash

!!! the Crash Reporter will not prompt you. There is also nothing in the Editor.log about a crash, though Windows will intercept it and asks you if you want to debug it.

You will get the same crash every time you try to open that project again and again - to test that, you can download and open the attached project with Unity 2019.3.0a10.

Cannot reproduce this issue in 2019.2.0b10, 2019.3.0a9