monitor: Use sdbusplus::bus::match::rules

Change-Id: I96ed7de07acfc864c497a0130c3e5afab579d21d
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/monitor/tach_sensor.cpp b/monitor/tach_sensor.cpp
index a4ebcd9..8d8d37a 100644
--- a/monitor/tach_sensor.cpp
+++ b/monitor/tach_sensor.cpp
@@ -126,11 +126,8 @@
 
 std::string TachSensor::getMatchString(const std::string& interface)
 {
-    return std::string("type='signal',"
-                       "interface='org.freedesktop.DBus.Properties',"
-                       "member='PropertiesChanged',"
-                       "arg0namespace='" + interface + "',"
-                       "path='" + _name + "'");
+    return sdbusplus::bus::match::rules::propertiesChanged(
+            _name, interface);
 }