chore(package): update @types/fluent-ffmpeg to version 2.1.3 (#786)

package.json

@@ -123,7 +123,7 @@
   },
   "devDependencies": {
     "@types/body-parser": "1.16.5",
-    "@types/fluent-ffmpeg": "2.1.2",
+    "@types/fluent-ffmpeg": "2.1.3",
     "@types/glob": "5.0.32",
     "@types/mime": "1.3.1",
     "@types/raven": "2.1.2",