Add submission # 507

ArduinoBot · ArduinoBot · commit 7089f00f02c6 · 2021-09-21T22:56:40.000Z
#507
diff --git a/registry.txt b/registry.txt
@@ -4349,3 +4349,4 @@ https://github.com/Frederik-Eberhard/Excelsior.git|Contributed|Excelsior
 https://github.com/khoih-prog/ESP32_PWM.git|Contributed|ESP32_PWM
 https://gitlab.com/tamctec/ft62x6-arduino.git|Contributed|TAMC_FT62X6
 https://github.com/Phoenix1747/MQ135.git|Contributed|MQ135
+https://github.com/khoih-prog/ESP8266_PWM.git|Contributed|ESP8266_PWM
