sensor: add relative humidity

Change-Id: I84f37194adbcaf99b4c426a8d51afc738bd6a799
diff --git a/yaml/xyz/openbmc_project/Sensor/Threshold/SoftShutdown.interface.yaml b/yaml/xyz/openbmc_project/Sensor/Threshold/SoftShutdown.interface.yaml
index a4522da..daf7078 100644
--- a/yaml/xyz/openbmc_project/Sensor/Threshold/SoftShutdown.interface.yaml
+++ b/yaml/xyz/openbmc_project/Sensor/Threshold/SoftShutdown.interface.yaml
@@ -8,6 +8,7 @@
       current
       energy
       fan_tach
+      humidity
       power
       pressure
       temperature