Update changelog

This is mainly to give me a version number I can use in other packages'
dependencies.

Signed-off-by: Simon McVittie <smcv@collabora.com>
6 jobs for master in 7 minutes and 56 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test
manual #40338
allowed to fail manual
build:arch
passed #40334
build:asan

00:03:15

passed #40337
build:bionic

00:07:49

passed #40336
build:buster

00:07:40

passed #40335
build:stretch

00:07:56

passed #40333
build:ubsan

00:03:33