Add boto pronunciation and description to README (#3216)

Author: tim-finnigan

README.rst

@@ -12,6 +12,8 @@ services that are supported.
 
 Boto3 is maintained and published by `Amazon Web Services`_.
 
+Boto (pronounced boh-toh) was named after the fresh water dolphin native to the Amazon river. The name was chosen by the author of the original Boto library, Mitch Garnaat, as a reference to the company.
+
 Notices
 -------