CB-11795 Add 'protective' entry to cordovaDependencies

The entry is required to protect end-users from fetching edge versions of the plugin by incompatible version of cordova. This also assumes that we will not introduce any regressions in compatibility w/ cordova in minor and patch releases. On every major release we will need to add similar entry with _next_ major version.

 This closes #19
diff --git a/package.json b/package.json
index 05623ae..45038e1 100644
--- a/package.json
+++ b/package.json
@@ -34,6 +34,13 @@
   },
   "author": "Apache Software Foundation",
   "license": "Apache-2.0",
+  "engines": {
+    "cordovaDependencies": {
+      "2.0.0": {
+        "cordova": ">100"
+      }
+    }
+  },
   "devDependencies": {
     "jshint": "^2.6.0"
   }