Crons docs for PowerShell

[bruno-garcia]

Turns out one of the first users of ".NET" on Crons is actually using PowerShell.
And I realize we don't have Crons on the PowerShell docs.

https://docs.sentry.io/platforms/powershell/

cc @vaind

[getsantry]

Routing to @getsentry/product-owners-crons for triage ⏲️