Update optionator to 0.8.1
diff --git a/package.json b/package.json
index ea67d68..2d73dbd 100644
--- a/package.json
+++ b/package.json
@@ -34,7 +34,7 @@
         "estraverse": "^1.9.1",
         "esutils": "^2.0.2",
         "esprima": "^2.7.1",
-        "optionator": "^0.5.0"
+        "optionator": "^0.8.1"
     },
     "optionalDependencies": {
         "source-map": "~0.2.0"