Improve support for YML arrays in New-ADOPipeline #125

When using YML arrays in a PowerShell step you need to convert it into a array by doing, as far as I know, something like this:

$requiredModules = "${{ join(';',parameters.requiredModules) }}" -split ';' | Where-Object { $_ }

1. Join the array into a string with the pipeline join function
2. Split the now string into a PowerShell array
3. Use ... | Where-Object { $_ } to get rid of any null values (added if passing in [])

Currently the output generated looks something like this:

$parameters.requiredModules -split ';' -replace '^[''"]' -replace  '[''"]$'