Use JupyterLite for try.jupyter.org (#682)

.gitignore

@@ -2,6 +2,7 @@ _site
 Gemfile.lock
 .DS_Store
 .jekyll-metadata
+.jekyll-cache
 vendor
 .bundle
 .sass-cache

try.html

@@ -14,6 +14,13 @@
     Click the boxes below to learn how they work and to learn more.
     If you like one, you can find <a href="/install">installation instructions here</a>.
 
+    <br><br>
+    ⚠️<strong>Experimental</strong>⚠️ several of the environments below use the
+    <a href="https://jupyterlite.readthedocs.io/en/latest/">JupyterLite project</a> to provide a self-contained
+    Jupyter environment that runs in your browser. This is experimental technology and
+    may have some bugs, so please be patient and report any unexpected behavior in
+    <a href="https://github.com/jupyterlite/jupyterlite/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc">the JupyterLite repository</a>.
+
 kernels_copy: |
     Jupyter kernels allow you to use Jupyter interfaces and tools with <b>any programming language</b>.
     Below are interactive demos for a few languages to help demonstrate. You can also find
@@ -24,13 +31,13 @@
       description: The latest web-based interactive development environment
       src: try/jupyter.png
       alt: Jupyter logo - Launch JupyterLab demo Binder
-      url: https://mybinder.org/v2/gh/jupyterlab/jupyterlab-demo/HEAD?urlpath=lab/tree/demo
+      url: https://jupyter.org/try-jupyter/lab?path=notebooks%2FIntro.ipynb
 
     - title: Jupyter Notebook
       description: The original web application for creating and sharing computational documents
       src: try/python.svg
       alt: Python logo - Launch Jupyter Notebook demo Binder
-      url: https://mybinder.org/v2/gh/ipython/ipython-in-depth/HEAD?urlpath=tree/binder/Index.ipynb
+      url: https://jupyter.org/try-jupyter/retro/notebooks/?path=notebooks/Intro.ipynb
 
     - title: Voilà
       description: Share insights by converting notebooks into interactive dashboards