fix(package): update apollo-server-express to version 2.6.0

Closes #67

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
   },
   "dependencies": {
     "@gramps/gramps": "^1.0.0",
-    "apollo-server-express": "^1.3.2",
+    "apollo-server-express": "^2.6.0",
     "babel-core": "^6.26.0",
     "body-parser": "^1.18.2",
     "chalk": "^2.3.0",