check for git (#810)

Author: TylerLeonhardt

PowerShellEditorServices.build.ps1

@@ -22,8 +22,10 @@ $script:TargetFrameworksParam = "/p:TargetFrameworks=\`"$(if (!$script:IsUnix) {
 $script:SaveModuleSupportsAllowPrerelease = (Get-Command Save-Module).Parameters.ContainsKey("AllowPrerelease")
 $script:BuildInfoPath = [System.IO.Path]::Combine($PSScriptRoot, "src", "PowerShellEditorServices.Host", "BuildInfo", "BuildInfo.cs")
 
-# ignore changes to this file
-git update-index --assume-unchanged "$PSScriptRoot/src/PowerShellEditorServices.Host/BuildInfo/BuildInfo.cs"
+if (Get-Command git -ErrorAction SilentlyContinue) {
+    # ignore changes to this file
+    git update-index --assume-unchanged "$PSScriptRoot/src/PowerShellEditorServices.Host/BuildInfo/BuildInfo.cs"
+}
 
 if ($PSVersionTable.PSEdition -ne "Core") {
     Add-Type -Assembly System.IO.Compression.FileSystem