MAINT: Update front page notices (#159)

* MAINT: Update front page notices

* remove notice of migration to jupyter-book

Author: mmcky

lectures/intro.md

@@ -14,24 +14,6 @@ kernelspec:
 This website presents a set of lectures on Python programming for economics and finance, designed and written by
 [Thomas J. Sargent](http://www.tomsargent.com/) and [John Stachurski](http://johnstachurski.net/). This is the first text in the series, which focuses on programming in Python.
 
-```{admonition} New Build System
-[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 [[email protected]](mailto:[email protected])
-```
-
-```{admonition} News
-Tom Sargent, Chase Coleman, and Spencer Lyon have put together The [NYU Computational Social
-Science: Certificate Program](http://www.tomsargent.com/nyu_css.html).
-It uses many [quantecon](https://quantecon.org/lectures/index.html)
-resources. The program  aims to prepare students for either a graduate program in the social
-sciences or for a career as a data analyst or computational social scientist.
-
-[Applications and additional information are available here](https://as.nyu.edu/content/nyu-as/as/departments/computational-social-science.html)
-```
-
 For an overview of the series, see [this page](https://quantecon.org/python-lectures/)
 
 ```{tableofcontents}