update badge

Author: v1rtl

README.md

@@ -1,7 +1,7 @@
 # superfetch
 
 [![GitHub Workflow Status][gh-actions-img]][github-actions]
-[![Codecov][codecov-badge]][codecov] [![][docs-badge]][docs]
+[![Codecov][cov-badge]][cov] [![][docs-badge]][docs]
 
 HTTP Server testing library inspired by
 [node-supertest-fetch](https://github.com/jwalton/node-supertest-fetch).
@@ -51,8 +51,8 @@ run()
 ```
 
 [gh-actions-img]: https://img.shields.io/github/actions/workflow/status/deno-libs/superfetch/main.yml?branch=master&style=for-the-badge&logo=github
-[codecov]: https://codecov.io/gh/deno-libs/superfetch
+[cov]: https://coveralls.io/github/deno-libs/superfetch
 [github-actions]: https://github.com/deno-libs/superfetch/actions
-[codecov-badge]: https://img.shields.io/codecov/c/gh/deno-libs/superfetch?style=for-the-badge
+[cov-badge]: https://img.shields.io/coverallsCoverage/github/deno-libs/superfetch?style=for-the-badge
 [docs-badge]: https://img.shields.io/github/v/release/deno-libs/superfetch?color=yellow&label=Docs&logo=deno&style=for-the-badge
 [docs]: https://doc.deno.land/https/deno.land/x/superfetch/mod.ts