Support linux agents

[Havunen]

When running task stephane-eyskens.apim.apimcreateorupdateproduct.apimcreateorupdateproduct@4 on 'ubuntu-latest' image it fails to following exception:

##[error]The current operating system is not capable of running this task. That typically means the task was written for Windows only. For example, written for Windows Desktop PowerShell.

I'm guessing this is because of used power shell version 3. https://github.com/stephaneey/azure-apim-extension/blob/master/apimcreateorupdateproduct/v4/task.json#L258-L260

Powershell 7 runs on linux and windows, maybe this template could be updated to use newer version?

[nishantpandey107]

any fix for this task ? @Havunen

[Havunen]

we migrated all our devops tasks to bicep... and removed this plugin