Add pressure sensor device class (#1713)

src/common/entity/sensor_icon.js

@@ -6,6 +6,7 @@ const fixedDeviceClassIcons = {
   humidity: 'hass:water-percent',
   illuminance: 'hass:brightness-5',
   temperature: 'hass:thermometer',
+  pressure: 'hass:gauge'
 };
 
 export default function sensorIcon(state) {

src/util/hass-attributes-util.js

@@ -31,7 +31,8 @@ hassAttributeUtil.DOMAIN_DEVICE_CLASS = {
     'battery',
     'humidity',
     'illuminance',
-    'temperature'
+    'temperature',
+    'pressure'
   ],
 };