Merge pull request #2432 from recrof/kiss-radio-everywhere

kiss radio: added stm32 support + envs in platformio.ini

variants/heltec_e290/platformio.ini

@@ -162,3 +162,8 @@ lib_deps =
   ${Heltec_E290_base.lib_deps}
   ${esp32_ota.lib_deps}
   bakercp/CRC32 @ ^2.0.0
+
+[env:Heltec_E290_kiss_modem]
+extends = Heltec_E290_base
+build_src_filter = ${Heltec_E290_base.build_src_filter}
+  +<../examples/kiss_modem/>