update library.properties

Author: smdn

library.properties

@@ -3,7 +3,8 @@ version=1.0
 author=smdn
 maintainer=smdn <smdn@smdn.jp>
 sentence=A library for the MH-Z19 series NDIR CO2 sensor module, for the Arduino framework.
-paragraph=A library for the MH-Z19 series NDIR CO2 sensor module, for the Arduino framework.
+paragraph=This library only supports retrieving measurement values by the serial communication. Retrieving measurement values from the PWM signals is not supported.
 category=Sensors
 url=https://github.com/smdn/MHZ19X-ArduinoFramework
-architectures=*
+architectures=*
+includes=MHZ19X.h