stop using the legacy build system for the demo project

Author: michaelhenry

Example/Demo.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

@@ -2,8 +2,6 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
-	<key>BuildSystemType</key>
-	<string>Original</string>
 	<key>PreviewsEnabled</key>
 	<false/>
 </dict>