Update to JupyterLite 0.6

Author: SylvainCorlay

.github/workflows/deploy-github-page.yml

@@ -70,7 +70,7 @@ jobs:
         shell: bash -l {0}
         run: |
           set -e
-          micromamba create -n xeus-lite-host jupyterlite-core jupyter_server
+          micromamba create -n xeus-lite-host jupyterlite-core=0.6 jupyter_server
           micromamba activate xeus-lite-host
           cd build/test
           # Fresh install browsers, and run Emscripten tests in them