Add Arduino AlPlc_PMC library (arduino#2547)

Author: manchoz

repositories.txt

@@ -5635,3 +5635,4 @@ https://github.com/Flinduino/Flinders_ENGR2781
 https://github.com/acksen/AcksenPump
 https://github.com/toannv17/DHT-Sensors-Non-Blocking
 https://github.com/arduino-libraries/AlPlc_Opta
+https://github.com/arduino-libraries/AlPlc_PMC