Remove @jonboulle as a maintainer

Jon has been unresponsive and last made project activity was nearly 2 years ago.

We thank Jon for his contributions and he was instrumental in helping getting OCI off the ground.

See #834

Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

MAINTAINERS

@@ -1,7 +1,6 @@
 Brendan Burns <bburns@microsoft.com> (@brendandburns)
 Jon Johnson <jonjohnson@google.com> (@jonjohnsonjr)
 John Starks <jostarks@microsoft.com> (@jstarks)
-Jonathan Boulle <jon@nstack.com> (@jonboulle)
 Stephen Day <stevvooe@gmail.com> (@stevvooe)
 Vincent Batts <vbatts@hashbangbash.com> (@vbatts)
 Aleksa Sarai <asarai@suse.de> (@cyphar)