Update author email

Author: wch

setup.cfg

@@ -2,7 +2,7 @@
 name = shiny
 version = attr: shiny.__version__
 author = Winston Chang
-author_email = winston@rstudio.com
+author_email = winston@posit.co
 url = https://github.com/posit-dev/py-shiny
 description = A web development framework for Python.
 long_description = file: README.md