chore(deps): pin dependency graphql-cli to v2.16.0-beta.6

Author: renovate-bot

package.json

@@ -21,7 +21,7 @@
     "graphql-tools": "2.23.1"
   },
   "devDependencies": {
-    "graphql-cli": "^2.16.0-beta.6",
+    "graphql-cli": "2.16.0-beta.6",
     "@types/graphql": "0.13.1",
     "@types/node": "10.1.4",
     "typescript": "2.8.3"

yarn.lock

@@ -46,6 +46,10 @@
   version "10.1.4"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-10.1.4.tgz#606651d3f8a8bec08b8cb262161aab9209f4a29d"
 
+"@types/node@^9.4.6":
+  version "9.6.22"
+  resolved "https://registry.yarnpkg.com/@types/node/-/node-9.6.22.tgz#05b55093faaadedea7a4b3f76e9a61346a6dd209"
+
 accepts@~1.3.5:
   version "1.3.5"
   resolved "https://registry.yarnpkg.com/accepts/-/accepts-1.3.5.tgz#eb777df6011723a3b14e8a72c0805c8e86746bd2"
@@ -1004,7 +1008,7 @@ graphql-cli-prepare@1.4.19:
     graphql-static-binding "0.9.3"
     lodash "4.17.5"
 
-graphql-cli@^2.16.0-beta.6:
+graphql-cli@2.16.0-beta.6:
   version "2.16.0-beta.6"
   resolved "https://registry.yarnpkg.com/graphql-cli/-/graphql-cli-2.16.0-beta.6.tgz#3bfca7366aa38edc1f446d1bcd95fe93df2513ea"
   dependencies: