Update README.md

Author: gares

README.md

@@ -1,4 +1,6 @@
-[![Actions Status](https://github.com/LPCIC/coq-elpi/workflows/CI/badge.svg)](https://github.com/LPCIC/coq-elpi/actions)
+[![Docker CI](https://github.com/LPCIC/coq-elpi/actions/workflows/main.yml/badge.svg)](https://github.com/LPCIC/coq-elpi/actions/workflows/main.yml)
+[![Nix CI](https://github.com/LPCIC/coq-elpi/actions/workflows/nix-action-coq-8.19.yml/badge.svg)](https://github.com/LPCIC/coq-elpi/actions/workflows/nix-action-coq-8.19.yml)
+[![DOC](https://github.com/LPCIC/coq-elpi/actions/workflows/doc.yml/badge.svg)](https://github.com/LPCIC/coq-elpi/actions/workflows/doc.yml)
 [![project chat](https://img.shields.io/badge/zulip-join_chat-brightgreen.svg)](https://coq.zulipchat.com/#narrow/stream/253928-Elpi-users.20.26.20devs)
 <img align="right" src="https://github.com/LPCIC/coq-elpi/raw/master/etc/logo.png" alt="Coq-Elpi logo" width="25%" />