chore(deps): update dependency typescript to v3.4.5

Author: renovate-bot

package.json

@@ -31,7 +31,7 @@
     "ts-jest": "23.10.5",
     "tslint": "5.12.1",
     "tslint-config-prettier": "1.18.0",
-    "typescript": "3.3.3"
+    "typescript": "3.4.5"
   },
   "homepage": "https://github.com/jfairley/github-slack-bot#readme",
   "keywords": [