refactor variants to use standard firmware type suffixes

variants/tiny_relay/platformio.ini

@@ -15,7 +15,7 @@ build_flags = ${stm32_base.build_flags}
 build_src_filter = ${stm32_base.build_src_filter}
   +<../variants/tiny_relay>
 
-[env:Tiny_Relay-repeater]
+[env:Tiny_Relay_repeater]
 extends = Tiny_Relay
 build_flags = ${Tiny_Relay.build_flags}
   -D ADVERT_NAME='"tiny_relay Repeater"'
@@ -23,7 +23,7 @@ build_flags = ${Tiny_Relay.build_flags}
 build_src_filter = ${Tiny_Relay.build_src_filter}
   +<../examples/simple_repeater/main.cpp>
 
-[env:Tiny_Relay-sensor]
+[env:Tiny_Relay_sensor]
 extends = Tiny_Relay
 build_flags = ${Tiny_Relay.build_flags}
   -D ADVERT_NAME='"tiny_relay Sensor"'