ConfigStep: start maintenance with Git on macOS

For the 20.10.178 release, we only promoted background maintenance via
Git and cron for the Linux platform because it did not have a service
project. We are now removing the service on macOS, so use the background
maintenance on all platforms _except_ Windows.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>

Scalar.Common/Maintenance/ConfigStep.cs

@@ -303,7 +303,7 @@ namespace Scalar.Common.Maintenance
                 return true;
             }
 
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
             {
                 // We still use Scalar.Service on this platform
                 error = null;