Add of SONOFF RFR3 environment

Relay ok
Button press ok
RF reception 433toMQTT ok
To have the RF reception you need to connect D0 of SYN470 to GPIO4 of ESP8285. Instruction to follow. Do not do that if you are not confortable with soldering and don't have an electrical background.

platformio.ini

@@ -22,6 +22,7 @@ extra_configs =
 ;you can also adapt the modules by removing the corresponding lines in the env detail  ;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+;default_envs = sonoff-basic-rfr3
 ;default_envs = rfbridge
 ;default_envs = esp32dev-all
 ;default_envs = esp32dev-rf
@@ -299,6 +300,24 @@ build_flags =
   '-DGateway_Name="OpenMQTTGateway_ESP8266_RF"'
 board_build.flash_mode = dout
 
+[env:sonoff-basic-rfr3]
+platform = ${com.esp8266_platform}
+board = esp8285
+lib_deps =
+  ${com-esp.lib_deps}
+  ${libraries.rc-switch}
+  ${libraries.esp8266_mdns}
+build_flags = 
+  ${com-esp.build_flags}
+  '-DZactuatorONOFF="ONOFF"'
+  '-DZsensorGPIOInput="GPIOInput"'
+  '-DACTUATOR_ONOFF_PIN=12'
+  '-DGPIOInput_PIN=0'
+  '-DRF_RECEIVER_PIN=4'
+  '-DZgatewayRF="RF"'
+  '-DGateway_Name="OpenMQTTGateway_SONOFF_BASIC_RFR3"'
+board_build.flash_mode = dout
+
 [env:atmega-all]
 platform = ${com.atmelavr_platform}
 board = megaatmega2560