docs: Fix codecov readme image

README.md

@@ -3,7 +3,7 @@
 [![Github Actions](https://github.com/avaly/backup-to-cloud/actions/workflows/tests.yaml/badge.svg)](https://github.com/avaly/backup-to-cloud/actions)
 [![NPM version](https://img.shields.io/npm/v/backup-to-cloud.svg?style=flat)](https://www.npmjs.com/package/backup-to-cloud)
 [![Install size](https://packagephobia.now.sh/badge?p=backup-to-cloud)](https://packagephobia.now.sh/result?p=backup-to-cloud)
-[![Codecov branch](https://img.shields.io/codecov/c/github/avaly/backup-to-cloud/master.svg?style=flat-square)](https://codecov.io/gh/avaly/backup-to-cloud)
+[![Codecov branch](https://img.shields.io/codecov/c/github/avaly/backup-to-cloud/main.svg?style=flat-square)](https://codecov.io/gh/avaly/backup-to-cloud)
 
 A simple backup tool which uploads encrypted files to S3, in batches.