Upgrade platyPS from Version 0.5 to 0.9 (#869)

* Upgrade to platyPS Version 0.9

* improve check, error message and spelling in build tools (and a PSSA warning about incorrect comparison with $null

* fix wrong version number

.build.ps1

@@ -202,10 +202,10 @@ task buildDocs -Inputs $bdInputs -Outputs $bdOutputs {
     Copy-Item -Path $docsPath\about_PSScriptAnalyzer.help.txt -Destination $outputDocsPath -Force
 
     # Build documentation using platyPS
-    if ((Get-Module PlatyPS -ListAvailable) -eq $null) {
-        throw "Cannot find PlatyPS. Please install it from https://www.powershellgallery.com."
+    if ($null -eq (Get-Module platyPS -ListAvailable -Verbose:$verbosity | Where-Object { $_.Version -ge 0.9 })) {
+        throw "Cannot find platyPS of version greater or equal to 0.9. Please install it from https://www.powershellgallery.com/packages/platyPS/ using e.g. the following command: Install-Module platyPS"
     }
-    Import-Module PlatyPS
+    Import-Module platyPS
     if (-not (Test-Path $markdownDocsPath -Verbose:$verbosity)) {
         throw "Cannot find markdown documentation folder."
     }

README.md

@@ -82,7 +82,7 @@ Exit
 ### From Source
 
 * [.NET Core 2.1.4 SDK](https://github.com/dotnet/core/blob/master/release-notes/download-archives/2.0.5-download.md)
-* [PlatyPS 0.5.0 or greater](https://github.com/PowerShell/platyPS)
+* [PlatyPS 0.9.0 or greater](https://github.com/PowerShell/platyPS/releases)
 * Optionally but recommended for development: [Visual Studio 2017](https://www.visualstudio.com/downloads/)
 
 #### Steps

appveyor.yml

@@ -17,7 +17,7 @@ cache:
 
 # Install Pester
 install:
-    - ps: nuget install platyPS -Version 0.5.0 -source https://www.powershellgallery.com/api/v2 -outputDirectory "$Env:ProgramFiles\WindowsPowerShell\Modules\." -ExcludeVersion
+    - ps: nuget install platyPS -Version 0.9.0 -source https://www.powershellgallery.com/api/v2 -outputDirectory "$Env:ProgramFiles\WindowsPowerShell\Modules\." -ExcludeVersion
     - ps: |
         $requiredPesterVersion = '3.4.0'
         $pester = Get-Module Pester -ListAvailable | Where-Object { $_.Version -eq $requiredPesterVersion }

build.ps1

@@ -95,13 +95,13 @@ if ($BuildDocs)
     Copy-Item -Path $docsPath\about_PSScriptAnalyzer.help.txt -Destination $outputDocsPath -Force -Verbose:$verbosity
 
     # Build documentation using platyPS
-    if ((Get-Module PlatyPS -ListAvailable -Verbose:$verbosity) -eq $null)
+    if ($null -eq (Get-Module platyPS -ListAvailable -Verbose:$verbosity | Where-Object { $_.Version -ge 0.5 }))
     {
-        throw "Cannot find PlatyPS. Please install it from https://www.powershellgallery.com."
+        "Cannot find platyPS. Please install it from https://www.powershellgallery.com/packages/platyPS/ using e.g. the following command: Install-Module platyPS"
     }
-    if ((Get-Module PlatyPS -Verbose:$verbosity) -eq $null)
+    if ((Get-Module platyPS -Verbose:$verbosity) -eq $null)
     {
-        Import-Module PlatyPS -Verbose:$verbosity
+        Import-Module platyPS -Verbose:$verbosity
     }
     if (-not (Test-Path $markdownDocsPath -Verbose:$verbosity))
     {