feat(doctor): update doctor to 1.7.0 version

Remove unzip as dependency from doctor package in order to support out of the box new versions of nodejs

Author: Fatme

npm-shrinkwrap.json

@@ -56,7 +56,7 @@
     "minimatch": "3.0.2",
     "mkdirp": "0.5.1",
     "mute-stream": "0.0.5",
-    "nativescript-doctor": "1.6.0",
+    "nativescript-doctor": "1.7.0",
     "nativescript-preview-sdk": "0.3.0",
     "open": "0.0.5",
     "ora": "2.0.0",