Add support for FYSETC F6 V1.3 board (#12527)

platformio.ini

@@ -344,3 +344,16 @@ lib_ignore  =
   TMC26XStepper
   c1921b4
 src_filter  = ${common.default_src_filter} +<src/HAL/HAL_ESP32>
+
+#
+# FYSETC F6 V1.3
+#
+[env:fysetc_f6_13]
+platform          = atmelavr
+framework         = arduino
+board             = fysetc_f6_13
+build_flags       = ${common.build_flags}
+board_build.f_cpu = 16000000L
+lib_deps          = ${common.lib_deps}
+src_filter        = ${common.default_src_filter} +<src/HAL/HAL_AVR>
+monitor_speed     = 250000