update news item on front page (#129)

Author: mmcky

lectures/intro.md

@@ -17,8 +17,9 @@ This website presents a set of lectures on Python programming for economics and
 ```{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) and this
-is the first in the QuantEcon lecture series to migrate. Please send feedback to [contact@quantecon.org](mailto:contact@quantecon.org)
+[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/)