added exact date one time

note that we can't say that the projects have pledged to drop support by Jan. 1, 2020, since not every project pledged that.

_sections/20-statement.md

@@ -19,7 +19,7 @@ transition has not been as quick as we hoped, we do see it taking place, with
 more and more people using, teaching and recommending Python 3.
 
 The developers of the Python language extended support of Python 2.7 from 2015
-to 2020, recognising that many people were still using Python 2. We believe
+to January 1, 2020, recognising that many people were still using Python 2. We believe
 that the extra 5 years is sufficient to transition off of Python 2, and our
 projects plan to stop supporting Python 2 when upstream support ends in 2020,
 if not before. We will then be able to simplify our code and take advantage of