chore(package): update typedoc to version 0.15.8

Closes #40

Author: greenkeeper[bot]

package.json

@@ -61,7 +61,7 @@
     "tap-summary": "^4.0.0",
     "tape-run": "^5.0.0",
     "tslint": "^5.13.1",
-    "typedoc": "^0.14.2",
+    "typedoc": "^0.15.8",
     "typescript": "^3.3.3333",
     "typescript-formatter": "^7.2.2"
   },