fix Node 6 build (#7955)

Author: jeysal

package.json

@@ -19,7 +19,7 @@
     "ansi-styles": "^3.2.0",
     "babel-eslint": "^9.0.0",
     "babel-loader": "^8.0.5",
-    "babel-plugin-typescript-strip-namespaces": "^1.1.0",
+    "babel-plugin-typescript-strip-namespaces": "^1.1.1",
     "camelcase": "^5.0.0",
     "chalk": "^2.0.1",
     "codecov": "^3.0.0",

yarn.lock

@@ -2610,10 +2610,10 @@ babel-plugin-syntax-trailing-function-commas@^7.0.0-beta.0:
   resolved "https://registry.yarnpkg.com/babel-plugin-syntax-trailing-function-commas/-/babel-plugin-syntax-trailing-function-commas-7.0.0-beta.0.tgz#aa213c1435e2bffeb6fca842287ef534ad05d5cf"
   integrity sha512-Xj9XuRuz3nTSbaTXWv3itLOcxyF4oPD8douBBmj7U9BBC6nEBYfyOJYQMf/8PJAFotC62UY5dFfIGEPr7WswzQ==
 
-babel-plugin-typescript-strip-namespaces@^1.1.0:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/babel-plugin-typescript-strip-namespaces/-/babel-plugin-typescript-strip-namespaces-1.1.0.tgz#7f8b022505bc742905801f9c41dd93f08f34ffc4"
-  integrity sha512-69kdF5HJoSIdgTVtHDor6XGJzVcxF5Hh92Rnh+rcitBZpj0pVU3Go0CrNJdPog6uoTcB90Ifk9O55FPZg0XN4w==
+babel-plugin-typescript-strip-namespaces@^1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/babel-plugin-typescript-strip-namespaces/-/babel-plugin-typescript-strip-namespaces-1.1.1.tgz#160433b17e424b57cf72e3b4d8f08195ad28d7fd"
+  integrity sha512-dVB9caEANbEVwUylL8g3lsYU5JjaXE2KNIVLib3KVcGJF32QunxvQqP6kf+lzW/fyDed/zWD/e/hdyimyc/79Q==
 
 [email protected]:
   version "6.23.0"