[__jitsi_meet] Fix task dependencies and pull key locally

Following discussion in
cdist!994
we added a `--source` parameter that can be used to feed a specific key with the
`__apt_key` type. We now use that instead of downloading the key from Jitsi's
servers.
2 jobs for jitsi-fix-versioning in 1 minute and 12 seconds (queued for 1 minute and 12 seconds)
Status Job ID Name Coverage
  Test
passed #9131
manpages

00:00:28

passed #9130
shellcheck

00:00:43