Update sgp30_simpletest.py

Corrected spell error

Author: pandianmn

examples/sgp30_simpletest.py

@@ -16,7 +16,7 @@
 print("SGP30 serial #", [hex(i) for i in sgp30.serial])
 
 sgp30.set_iaq_baseline(0x8973, 0x8AAE)
-sgp30.set_iaq_relative_humidity(celcius=22.1, relative_humidity=44)
+sgp30.set_iaq_relative_humidity(celsius=22.1, relative_humidity=44)
 
 elapsed_sec = 0