Align list of conda-forge robotology-superbuild dependencies between …

…CI and docs (#911)

doc/conda-forge.md

@@ -127,7 +127,7 @@ of the robotology-superbuild.**
 Once you activated it, you can install packages in it. In particular the dependencies for the robotology-superbuild can be installed as:
 ~~~
 mamba install -c conda-forge cmake compilers make ninja pkg-config
-mamba install -c conda-forge ace asio boost eigen gazebo glew glfw gsl ipopt libjpeg-turbo libmatio libode libxml2 nlohmann_json opencv pkg-config portaudio qt sdl sdl2 sqlite tinyxml spdlog
+mamba install -c conda-forge ace asio boost eigen gazebo glew glfw gsl ipopt irrlicht libjpeg-turbo libmatio libode libxml2 nlohmann_json opencv pkg-config portaudio qt sdl sdl2 sqlite tinyxml spdlog
 ~~~
 
 If you are on **Linux**, you also need to install also the following packages: