Added Istanbul Badges Readme wich provides us with code coverage badges

Author: igor-vorontsov-ew

README.md

@@ -2,6 +2,11 @@
 [![Maintenance](https://img.shields.io/badge/Maintained%3F-yes-green.svg)](https://github.com/extrawest/ocpp-node-ts)
 ![GitHub release](https://img.shields.io/github/v/release/extrawest/ocpp-node-ts)
 [![GitHub tag](https://img.shields.io/github/v/tag/extrawest/ocpp-node-ts)](https://github.com/extrawest/ocpp-node-ts/tags/)
+#### Test coverage
+![Statements](https://img.shields.io/badge/statements-100%25-brightgreen.svg?style=flat)
+![Branches](https://img.shields.io/badge/branches-100%25-brightgreen.svg?style=flat)
+![Functions](https://img.shields.io/badge/functions-100%25-brightgreen.svg?style=flat)
+![Lines](https://img.shields.io/badge/lines-100%25-brightgreen.svg?style=flat)
 # Extrawest OCPP 2.0.1 package
 
 Based on great package [sepych/ocpp-ts][sepych/ocpp-ts] for OCPP 1.6 version.

package-lock.json

@@ -45,13 +45,14 @@
     "eslint": "^8.34.0",
     "eslint-config-airbnb": "^19.0.4",
     "eslint-config-airbnb-typescript": "^17.0.0",
+    "istanbul-badges-readme": "^1.8.5",
     "jest": "^28.1.0",
+    "jest-websocket-mock": "^2.4.0",
     "json-schema-to-typescript": "^11.0.4",
     "mock-socket": "^9.2.1",
     "ts-jest": "^28.0.2",
     "ts-node": "^10.9.1",
-    "typescript": "^4.9.5",
-    "jest-websocket-mock": "^2.4.0"
+    "typescript": "^4.9.5"
   },
   "jest": {
     "moduleFileExtensions": [
@@ -64,6 +65,7 @@
     "transform": {
       "^.+\\.(t|j)s$": "ts-jest"
     },
+    "coverageReporters": ["json-summary"],
     "collectCoverageFrom": [
       "**/*.(t|j)s"
     ],