Update humans.txt for Bevan's last day

public/humans.txt

@@ -1,2 +1,17 @@
 GOV.UK is built by a team at the Government Digital Service (with thanks to Martha!) in London,
 Bristol and Manchester.  If you'd like to join us, see https://gdscareers.gov.uk/
+
+Today we're saying goodbye to Bevan Loon, one of our Lead Developers. Bevan
+joined GOV.UK in 2016 and has been chipping away behind the scenes ever since.
+
+Over the years Bevan's worked on many things - the consolidation of content to a
+single GOV.UK Content Store, delivering a bespoke email notification system,
+leading efforts to improve the health of the platform and advocating for good
+pair programming practices.
+
+Bevan's been a core pillar of the developer community, teaching us all how to be
+better developers and better people. Almost single handedly running the GOV.UK
+Tech Fortnightly meeting.
+
+Bevan - thank you so much for all the work you've done and all the support
+you've given us. Good luck, we'll miss you!