add codecov badge

Author: dangowans

README.md

@@ -2,6 +2,7 @@
 
 [![npm (scoped)](https://img.shields.io/npm/v/%40cityssm/windows-unc-path-connect)](https://www.npmjs.com/package/@cityssm/windows-unc-path-connect)
 [![DeepSource](https://app.deepsource.com/gh/cityssm/node-windows-unc-path-connect.svg/?label=active+issues&show_trend=true&token=kMenIfdyEcHVDtebaPlgkjFy)](https://app.deepsource.com/gh/cityssm/node-windows-unc-path-connect/)
+[![codecov](https://codecov.io/gh/cityssm/node-windows-unc-path-connect/graph/badge.svg?token=37N29WMP5B)](https://codecov.io/gh/cityssm/node-windows-unc-path-connect)
 [![Coverage Testing](https://github.com/cityssm/node-windows-unc-path-connect/actions/workflows/coverage.yml/badge.svg)](https://github.com/cityssm/node-windows-unc-path-connect/actions/workflows/coverage.yml)
 
 Ensures a UNC path that requires a user name and password