fix linkchecker results

Author: mmcky

lectures/_config.yml

@@ -23,7 +23,9 @@ sphinx:
                        'https://ieeexplore.ieee.org/document/8757088',
                        'https://www.sciencedirect.com/science/article/pii/S1477388021000177',
                        'https://keras.io/',
-                       'https://data.oecd.org/']
+                       'https://data.oecd.org/',
+                       'https://www.reddit.com/',
+                       'https://openai.com']
     html_favicon: _static/lectures-favicon.ico
     html_theme: quantecon_book_theme
     html_static_path: ['_static']

lectures/workspace.md

@@ -121,7 +121,7 @@ This lecture takes you through the workings of two development environments.
 
 JupyterLab is a browser based development environment for Jupyter Notebooks, code scripts, and data files.
 
-You can [try JupyterLab in the browser](https://jupyter.org/try#jupyterlab) if you want to test it out before installing it locally.
+You can [try JupyterLab in the browser](https://jupyter.org/try-jupyter/lab/) if you want to test it out before installing it locally.
 
 You can install JupyterLab using pip