ci: Switch clazy job to debian-unstable image

10 jobs for fix/ci-clazy in 49 minutes (queued for 50 minutes and 39 seconds)
Status Job ID Name Coverage
  Test
passed #28655
clazy

00:03:13

passed #28656
qmllint

00:01:27

 
  Build
passed #28660
archlinux

00:02:26

passed #28659
debian-sid

00:00:57

passed #28658
neon-bionic

00:01:20

passed #28657
ubuntu-trusty

00:01:20

 
  Deploy
passed #28663
android

00:13:16

passed #28661
linux-appimage

00:15:18

passed #28664
mac-osxcross

00:09:49

passed #28662
windows-mxe

00:09:38