Keep node type definitions at version 9.6.7 (close snowplow#649)

Author: mhadam

core/package.json

@@ -1,12 +1,13 @@
 {
   "name": "snowplow-tracker-core",
-  "version": "0.6.0",
+  "version": "0.6.1-beta1",
   "devDependencies": {
     "grunt": "0.4.5",
     "intern": "3.3.2",
     "dts-generator": "^2.0.0",
     "grunt-ts": "5.5.1",
     "typescript": "2.2.2",
+    "@types/node": "^9.6.7",
     "@types/es6-shim": "0.31.34",
     "@types/uuid": "^2.0.29"
   },

package.json

@@ -5,7 +5,7 @@
     "browser-cookie-lite": "0.3.1",
     "jstimezonedetect": "1.0.5",
     "lodash": "3.10.1",
-    "snowplow-tracker-core": "0.6.0",
+    "snowplow-tracker-core": "file:./core/",
     "murmurhash": "0.0.2",
     "uuid": "2.0.3",
     "sha1": "git://github.com/pvorb/node-sha1.git#910081c83f3661507d9d89e66e3f38d8b59d5559"