AboutPSProviders - Pester v5 compatibility

[vexx32]

Describe "Koan Bug, Issue, or Help Request"

• In the Environment Provider section, the $EnvironmentData variable is defined directly in the Describe. This will not work in Pester v5, it should be inside a BeforeAll{} block.
• In the allows you to cope, rename, or delete files koan of the FileSystem Provider, it runs into errors after the first run, since the file TESTNAME.tmp is not always properly cleaned up afterwards. It seems it is not always removed at the end of that It; we may need to be more stringent about how/when that exactly is removed.