Fix support date for v3.1 in readme

README.rst

@@ -99,7 +99,7 @@ The currently supported versions of Oscar are:
 +---------+----------------+
 | Version | End of support |
 +=========+================+
-| 3.1     | April 2021     |
+| 3.1     | April 2022     |
 +---------+----------------+
 | 3.0     | May 2021       |
 +---------+----------------+