xSQLServer: Quick fix for breaking changes in Pester (dsccommunity#813)

- Changes to xSQLServer
  - Changed so the maximum version to be installed is 4.0.6.0. Quick fix until we
    can resolve the unit tests (see issue dsccommunity#807).

CHANGELOG.md

@@ -8,6 +8,8 @@
     can be renamed back by the integration tests xSQLServerSetup so that the
     integration tests can run successfully.
     ([issue #774](https://github.com/PowerShell/xFailOverCluster/issues/774)).
+  - Changed so the maximum version to be installed is 4.0.6.0. Quick fix until we
+    can resolve the unit tests (see issue #807).
 - Changes to xSQLServerHelper
   - Changes to Connect-SQL and Import-SQLPSModule
     - Now it correctly loads the correct assemblies when SqlServer module is

appveyor.yml

@@ -7,7 +7,7 @@ install:
     - git clone https://github.com/PowerShell/DscResource.Tests
     - ps: Write-Verbose -Message "PowerShell version $($PSVersionTable.PSVersion)" -Verbose
     - ps: Import-Module "$env:APPVEYOR_BUILD_FOLDER\DscResource.Tests\AppVeyor.psm1"
-    - ps: Invoke-AppveyorInstallTask
+    - ps: Invoke-AppveyorInstallTask -PesterMaximumVersion '4.0.6.0'
 
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