Update README.md

Author: joaquimg

README.md

@@ -5,3 +5,5 @@ Experimental package with analysis and debugging tools for JuMP and MOI.
 [![Build Status](https://github.com/jump-dev/ModelAnalyzer.jl/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/jump-dev/ModelAnalyzer.jl/actions?query=workflow%3ACI)
 
 [![codecov](https://codecov.io/gh/jump-dev/ModelAnalyzer.jl/branch/main/graph/badge.svg)](https://codecov.io/gh/jump-dev/ModelAnalyzer.jl)
+
+[![dev](https://img.shields.io/badge/docs-dev-blue.svg)](https://jump-dev.github.io/ModelAnalyzer.jl/dev/)