MAINT: remove notice for jupyter-book (#178)

Author: mmcky

lectures/intro.md

@@ -14,14 +14,6 @@ kernelspec:
 This website presents a set of lectures on quantitative economic modeling, designed and written by
 [Thomas J. Sargent](http://www.tomsargent.com/) and [John Stachurski](http://johnstachurski.net/).
 
-```{admonition} News
-[QuantEcon](https://quantecon.org) is moving to the [Jupyter Book](https://jupyterbook.org/intro.html)
-build system for all of its projects. We are a founding member of the
-[Executable Books Project](https://github.com/executablebooks), an international collaboration to
-build open source tools that facilitate publishing using the Jupyter
-ecosystem. Please send feedback to [contact@quantecon.org](mailto:contact@quantecon.org)
-```
-
 For an overview of the series, see [this page](https://quantecon.org/python-lectures/)
 
 ```{tableofcontents}