Add missing DISCHRG state (#13787)

* Add missing ups.status states.

* Add missing DISCHRG state.

homeassistant/components/sensor/nut.py

@@ -113,6 +113,7 @@ STATE_TYPES = {
     'HB': 'High Battery',
     'RB': 'Battery Needs Replaced',
     'CHRG': 'Battery Charging',
+    'DISCHRG': 'Battery Discharging',
     'BYPASS': 'Bypass Active',
     'CAL': 'Runtime Calibration',
     'OFF': 'Offline',