add kiss radio env to most of the variants

variants/heltec_e213/platformio.ini

@@ -166,3 +166,8 @@ lib_deps =
   ${Heltec_E213_base.lib_deps}
   ${esp32_ota.lib_deps}
   bakercp/CRC32 @ ^2.0.0
+
+[env:Heltec_E213_kiss_modem]
+extends = Heltec_E213_base
+build_src_filter = ${Heltec_E213_base.build_src_filter}
+  +<../examples/kiss_modem/>