test(Coverage): Migrate to codecov

Author: cblanc

README.md

@@ -5,7 +5,7 @@
 > Validate & parse UK postcodes
 
 [![CircleCI](https://circleci.com/gh/ideal-postcodes/postcode.svg?style=svg)](https://circleci.com/gh/ideal-postcodes/postcode)
-[![Coverage Status](https://coveralls.io/repos/github/ideal-postcodes/postcode/badge.svg?branch=master)](https://coveralls.io/github/ideal-postcodes/postcode?branch=master)
+[![codecov](https://codecov.io/gh/ideal-postcodes/postcode/branch/master/graph/badge.svg)](https://codecov.io/gh/ideal-postcodes/postcode)
 [![Dependencies](https://david-dm.org/ideal-postcodes/postcode.svg)](https://david-dm.org/ideal-postcodes/postcode)
 [![Size](https://img.shields.io/bundlephobia/min/postcode.svg?style=flat)](https://bundlephobia.com/result?p=postcode)
 [![Downloads](https://img.shields.io/npm/dm/postcode.svg)](https://www.npmjs.com/package/postcode)

package-lock.json

@@ -19,7 +19,7 @@
     "@types/node": "~13.1.0",
     "benchmark": "~2.1.4",
     "chai": "~4.2.0",
-    "coveralls": "~3.0.2",
+    "codecov": "~3.6.1",
     "csv-parse": "~4.8.2",
     "install-npm-version": "~1.0.3",
     "mocha": "~6.2.0",
@@ -65,7 +65,7 @@
     "docs": "typedoc --mode file --excludePrivate --hideGenerator --excludeExternals --target ES5 --out docs/ --name 'Postcode.js' --theme minimal lib/",
     "build": "tsc",
     "benchmark": "npm run build && node benchmark.js",
-    "coverage": "nyc report --reporter=text-lcov | coveralls || true"
+    "coverage": "nyc report --reporter=text-lcov > coverage.lcov && codecov"
   },
   "repository": {
     "type": "git",