chore(package): update tslib to version 1.6.1

https://greenkeeper.io/

Author: greenkeeper[bot]

package.json

@@ -43,7 +43,7 @@
     "semver": "5.3.0",
     "should": "11.2.1",
     "ts-loader": "2.0.3",
-    "tslib": "1.6.0",
+    "tslib": "1.6.1",
     "tslint": "5.1.0",
     "tslint-loader": "3.5.2",
     "typedoc": "0.5.10",