Merge pull request #113 from csantero/bump-version-checker

require dep on ember-cli-version-checker 2.1.0

Author: chriskrycho

package.json

@@ -89,6 +89,7 @@
     "typescript": "^2.7.1"
   },
   "peerDependencies": {
+    "ember-cli-version-checker": "^2.1.0",
     "typescript": "^2.4.2"
   },
   "engines": {