pio: use gcc10.1 package from registry

ref.
https://github.com/platformio/platform-espressif8266/issues/224#issuecomment-667053958
https://bintray.com/platformio/dl-packages/toolchain-xtensa/2.100100.200706

code/platformio.ini

@@ -121,7 +121,7 @@ shared_libdeps_dir = libraries/
 # TODO: right now we depend on external toolchain url b/c toolchain version is hard-coded into the platform
 git_platform_packages =
     framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git
-    toolchain-xtensa @ https://github.com/earlephilhower/esp-quick-toolchain/releases/download/3.0.0-gnu12/x86_64-linux-gnu.xtensa-lx106-elf-0474ae9.200706.tar.gz
+    toolchain-xtensa @ ~2.100100.200706
 
 # XXX: 2.3.0 depends on these
 legacy_lib_deps =