Update Python 3.0's EOL date (#543)

> Python 3.0 is end-of-lifed with the release of Python 3.1.

https://www.python.org/download/releases/3.0/

> Python 3.1 final was released on June 27th, 2009.

https://www.python.org/download/releases/3.1/

Author: hugovk

devcycle.rst

@@ -134,7 +134,7 @@ For reference, here are the Python versions that most recently reached their end
 +------------------+--------------+----------------+----------------+----------------------------------+
 | 3.1              | :pep:`375`   | 2009-06-27     | 2012-04-09     | Benjamin Peterson                |
 +------------------+--------------+----------------+----------------+----------------------------------+
-| 3.0              | :pep:`361`   | 2008-12-03     | 2009-01-13     | Barry Warsaw                     |
+| 3.0              | :pep:`361`   | 2008-12-03     | 2009-06-27     | Barry Warsaw                     |
 +------------------+--------------+----------------+----------------+----------------------------------+
 | 2.6              | :pep:`361`   | 2008-10-01     | 2013-10-29     | Barry Warsaw                     |
 +------------------+--------------+----------------+----------------+----------------------------------+