Package testing documentation contains install tests, but should also include information on testing uninstall (and preferably upgrade)

## What New Or Updated Would You Like To See?

Add more testing instructions to https://docs.chocolatey.org/en-us/create/create-packages#testing-your-package and https://community.chocolatey.org/courses/creating-chocolatey-packages/building-testing-and-pushing, especially about uninstall but also about upgrading (both document pages currently only mention installation testing).

## Why Is It Needed?

Since Chocolatey is about keeping an installed system current, upgrades are way more frequent than installs. Also key part of software installs is that they can be uninstalled n a clean way.

So please add instructions for at least testing uninstall, but preferably also about upgrading.

## Additional Context?

Related: https://github.com/chocolatey/choco/issues/2850

Notes:

- for me `choco uninstall packageName --debug --verbose --source=.` was sufficient for testing uninstall of [my `setacl` pull request](https://github.com/bcurran3/ChocolateyPackages/pull/310), though it might be that the `--source=.` is not needed
- given I'm a relative notice on Chocolatey, I don't have hints for upgrade testing (I cannot test a `setacl` upgrade, as the [current 3.0.6 version requires a ZIP file download which has disappeared](https://github.com/bcurran3/ChocolateyPackages/issues/309#issuecomment-1268280494) and I have no system that has 3.0.6 installed through Chocolatey)