removes unecessary lcov-result-merger dependency (#547)

Author: zevdg

packages/messaging/package.json

@@ -18,7 +18,6 @@
   "dependencies": {
     "@firebase/messaging-types": "0.1.2",
     "@firebase/util": "0.1.10",
-    "lcov-result-merger": "^2.0.0",
     "tslib": "^1.9.0"
   },
   "devDependencies": {