Update development installation instructions in contributing.rst.

Author: HaudinFlorence

docs/source/contributing.rst

@@ -7,25 +7,39 @@ Contributing
 Development install
 -------------------
 
-**Note:** You will need :ref:`Node.js <https://nodejs.org/>` and :ref:`Docker <https://www.docker.com/>` to build the extension package.
+You need to create a development environment with `nodejs` and `jupyterlab` installed.  We are here proposing to use `micromamba`.
 
-The ``jlpm`` command is JupyterLab's pinned version of
-:ref:`yarn <https://yarnpkg.com/>` that is installed with JupyterLab. You may use
-:ref:`yarn <https://yarnpkg.com/>` or :ref:`npm <https://www.npmjs.com/>` in lieu of ``jlpm`` below.
+.. code-block:: bash
+
+    # Create an environment with micromamba and install nodejs and jupyterlab
+    micromamba create -n jupytercad_dev -c conda-forge nodejs jupyterlab -y
+
+You then need to clone the repository, proceed to installation and rebuild the extension.
 
 .. code-block:: bash
 
     # Clone the repo to your local environment
     git clone https://github.com/jupytercad/JupyterCAD.git
     # Change directory to the jupytercad directory
     cd JupyterCAD
-    # Install JupyterLab for jlpm
-    pip install jupyterlab
-    # Install package in development mode
-    python scripts/dev-install.py
+    # Install dependencies and the package in development mode
+    jlpm install
+    jlpm dev ## if you haven't Docker installed replace this line by `jlpm dev --no-occ-build`
     # Rebuild extension Typescript source after making changes
     jlpm run build
 
+**Note:** There are 2 possibilities for the installation. 
+
+1) either you are using [Docker](https://www.docker.com/) to build `@jupytercad/opencascade` package and you need to run `jlpm dev` in the commands above.
+
+2) or you are using a prebuilt version by calling `jlpm dev --no-occ-build` to install the package.
+
+
+**Note:** The `jlpm` command is JupyterLab's pinned version of
+[yarn](https://yarnpkg.com/) that is installed with JupyterLab. You may use
+`yarn` or `npm` in lieu of `jlpm` above.
+
+
 You can watch the source directory and run JupyterLab at the same time in different terminals to watch for changes in the extension's source and automatically rebuild the extension.
 
 .. code-block:: bash