fix(package): repository should point to a git+url

Author: ethan-ozelius-contentful

package.json

@@ -14,7 +14,7 @@
   },
   "repository": {
     "type": "git",
-    "url": "https://github.com/contentful/contentful-sdk-core.git"
+    "url": "git+https://github.com/contentful/contentful-sdk-core.git"
   },
   "author": "Contentful <opensource@contentful.com>",
   "license": "MIT",