Bump version to 0.14.4

Summary: As per title. 0.14.3 is out of the door, so it's time for the next version.

Test Plan:

make check

Reviewers: freetrader, sickpig, awemany, dagurval, #bitcoin_abc

Reviewed By: sickpig, #bitcoin_abc

Subscribers: Mengerian

Differential Revision: https://reviews.bitcoinabc.org/D337