feat: drop support for Xcode < 10

As AppStore now requires new published apps to be build with Xcode 10 or later, set this as requirement for building applications.

Author: rosen-vladimirov

npm-shrinkwrap.json

@@ -57,7 +57,7 @@
     "mkdirp": "0.5.1",
     "mute-stream": "0.0.5",
     "nativescript-dev-xcode": "0.2.0",
-    "nativescript-doctor": "1.9.2",
+    "nativescript-doctor": "1.10.0",
     "nativescript-preview-sdk": "0.3.4",
     "open": "0.0.5",
     "ora": "2.0.0",