MAINTAINERS: update my email address

I've recently switched employers and the current email address is out
of date.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20201027060253.353054-1-michael.roth@amd.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

MAINTAINERS

@@ -2427,7 +2427,7 @@ F: scripts/simplebench/
 
 QAPI
 M: Markus Armbruster <armbru@redhat.com>
-M: Michael Roth <mdroth@linux.vnet.ibm.com>
+M: Michael Roth <michael.roth@amd.com>
 S: Supported
 F: qapi/
 X: qapi/*.json
@@ -2471,7 +2471,7 @@ F: tests/data/qobject/qdict.txt
 T: git https://repo.or.cz/qemu/armbru.git qapi-next
 
 QEMU Guest Agent
-M: Michael Roth <mdroth@linux.vnet.ibm.com>
+M: Michael Roth <michael.roth@amd.com>
 S: Maintained
 F: qga/
 F: docs/interop/qemu-ga.rst