phosphor-dbus-monitor: Add sdeventplus DEPEND

An upcoming change will require that phospohr-dbus-monitor have
sdeventplus available.

Change-Id: Ief7e59ec542343272d03fa53e9b369606892e28e
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/recipes-phosphor/dbus/phosphor-dbus-monitor_git.bb b/recipes-phosphor/dbus/phosphor-dbus-monitor_git.bb
index dbac392..6a4485e 100644
--- a/recipes-phosphor/dbus/phosphor-dbus-monitor_git.bb
+++ b/recipes-phosphor/dbus/phosphor-dbus-monitor_git.bb
@@ -24,6 +24,7 @@
         phosphor-logging \
         autoconf-archive-native \
         sdbusplus-native \
+        sdeventplus \
         gtest \
         phosphor-snmp \
         "