Bug 1583690 [wpt PR 19278] - Update interfaces/proximity.idl, a=testonly

Automatic update from web-platform-tests
Update interfaces/proximity.idl (#19278)

Source: https://github.com/tidoust/reffy-reports/blob/1c5a999/ed/idl/proximity.idl
Build: https://travis-ci.org/tidoust/reffy-reports/builds/588932563
--

wpt-commits: 0428f3666991423c4093646f62dc737ec7046a99
wpt-pr: 19278

testing/web-platform/tests/interfaces/proximity.idl

@@ -3,7 +3,7 @@
 // (https://github.com/tidoust/reffy-reports)
 // Source: Proximity Sensor (https://w3c.github.io/proximity/)
 
-[Constructor(optional SensorOptions sensorOptions), SecureContext, Exposed=Window]
+[Constructor(optional SensorOptions sensorOptions = {}), SecureContext, Exposed=Window]
 interface ProximitySensor : Sensor {
   readonly attribute double? distance;
   readonly attribute double? max;