(GH-59) Correcting issue when running GitVersion

- GitVersion was being executed from the BuildScripts folder, therefore there were no AssemblyInfo files to update
- By passing in rootDirectory as the first parameter, it will be able to find and update the correct attributes

BuildScripts/default.ps1

@@ -415,7 +415,7 @@ Task -Name RunGitVersion -Depends __InstallGitVersion -Description "Execute the
 		exec {
 			if(isAppVeyor) {
 				Write-Output "Running on AppVeyor, so UpdateAssemblyInfo will be called."
-				& $gitVersionExe /output buildserver /UpdateAssemblyInfo true
+				& $gitVersionExe $rootDirectory /output buildserver /UpdateAssemblyInfo true
 				$script:version = $env:GitVersion_LegacySemVerPadded
 			} else {
 				$output = & $gitVersionExe