docs(readme): add badge to relative CI for client

Author: eliandoran

README.md

@@ -1,6 +1,9 @@
 # TriliumNext Notes
 
-![GitHub Sponsors](https://img.shields.io/github/sponsors/eliandoran) ![Docker Pulls](https://img.shields.io/docker/pulls/triliumnext/notes) ![GitHub Downloads (all assets, all releases)](https://img.shields.io/github/downloads/triliumnext/notes/total)
+![GitHub Sponsors](https://img.shields.io/github/sponsors/eliandoran?style=flat-square)
+![Docker Pulls](https://img.shields.io/docker/pulls/triliumnext/notes?style=flat-square)
+![GitHub Downloads (all assets, all releases)](https://img.shields.io/github/downloads/triliumnext/notes/total?style=flat-square)
+[![RelativeCI](https://badges.relative-ci.com/badges/Di5q7dz9daNDZ9UXi0Bp?branch=develop&style=flat-square)](https://app.relative-ci.com/projects/Di5q7dz9daNDZ9UXi0Bp)
 
 [English](./README.md) | [Chinese](./docs/README-ZH_CN.md) | [Russian](./docs/README.ru.md) | [Japanese](./docs/README.ja.md) | [Italian](./docs/README.it.md) | [Spanish](./docs/README.es.md)