Fix MSSQL support changelog inconsistency
Fix MSSQL support changelog inconsistency

This update was suggested by @obmsch's [1].

Release 5.20.8 introduced support for MSSQL 2014 and later, but the
corresponding changelog entry actually documented that as 2016 and later
while the 5.21.0 changelog indicated support for MSSQL 2014 (after
commit 98e7db89ba08c40dd491e83e0981d7b271b9bbcd).

[1]: https://github.com/ADOdb/ADOdb/commit/259602ce203b3820231e01e0690818ac38b6c65c

ipso/ADOdb,ipso/ADOdb