add awesome prometheus alerts repo

readme.md

@@ -838,6 +838,7 @@
 - [TikZ](https://github.com/xiaohanyu/awesome-tikz#readme) - Graph drawing packages for TeX/LaTeX/ConTeXt.
 - [Ad-Free](https://github.com/johnjago/awesome-ad-free#readme) - Ad-free alternatives.
 - [Prometheus](https://github.com/roaldnefs/awesome-prometheus#readme) - Open-source monitoring system.
+- [Prometheus Alerts](https://github.com/samber/awesome-prometheus-alerts) - Alerting rules for Prometheus setup
 - [Homematic](https://github.com/homematic-community/awesome-homematic#readme) - Smart home devices.
 - [Ledger](https://github.com/sfischer13/awesome-ledger#readme) - Double-entry accounting on the command-line.
 - [Web Monetization](https://github.com/thomasbnt/awesome-web-monetization#readme) - A free open web standard service that allows you to send money directly in your browser.