chore(deps): update dependency typescript to v2.8.1

Author: renovate-bot

package.json

@@ -29,7 +29,7 @@
     "@types/node": "8.5.7",
     "tslint": "5.8.0",
     "tslint-config-standard": "7.0.0",
-    "typescript": "2.6.2"
+    "typescript": "2.8.1"
   },
   "dependencies": {
     "express": "^4.15.3",

yarn.lock

@@ -2172,9 +2172,9 @@ type-is@^1.6.6, type-is@~1.6.15:
     media-typer "0.3.0"
     mime-types "~2.1.15"
 
-typescript@2.6.2:
-  version "2.6.2"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.6.2.tgz#3c5b6fd7f6de0914269027f03c0946758f7673a4"
+typescript@2.8.1:
+  version "2.8.1"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.8.1.tgz#6160e4f8f195d5ba81d4876f9c0cc1fbc0820624"
 
 ua-parser-js@^0.7.9:
   version "0.7.14"