support enum in parameters (#5838)

modules/openapi-generator/src/main/resources/powershell-experimental/api.mustache

@@ -28,6 +28,11 @@ function {{{vendorExtensions.x-powershell-method-name}}} {
     Param (
     {{#allParams}}
         [Parameter(Position = {{vendorExtensions.x-index}}{{#-first}}, ValueFromPipeline = $true{{/-first}}, ValueFromPipelineByPropertyName = $true, Mandatory = $false)]
+        {{#isEnum}}
+        {{#allowableValues}}
+        [ValidateSet({{#enumVars}}{{{value}}}{{^-last}}, {{/-last}}{{/enumVars}})]
+        {{/allowableValues}}
+        {{/isEnum}}
         [{{{vendorExtensions.x-powershell-data-type}}}]
         {{=<% %>=}}
         ${<%paramName%>},

samples/client/petstore/powershell-experimental/src/PSPetstore/API/PSPetApi.ps1

@@ -187,6 +187,7 @@ function Find-PSPetsByStatus {
     [CmdletBinding()]
     Param (
         [Parameter(Position = 0, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, Mandatory = $false)]
+        [ValidateSet("available", "pending", "sold")]
         [String[]]
         ${Status},
         [Switch]

samples/client/petstore/powershell-experimental/src/PSPetstore/PSPetstore.psd1

@@ -3,7 +3,7 @@
 #
 # Generated by: OpenAPI Generator Team
 #
-# Generated on: 4/4/20
+# Generated on: 4/6/20
 #
 
 @{