platform.txt: Override python3 anon pipe encoding to utf-8 for 'tools/sizes.py' (#8570)

Author: jjsuwa-sys3175

platform.txt

@@ -148,7 +148,7 @@ recipe.objcopy.eep.pattern=
 ## Create hex
 recipe.objcopy.hex.1.pattern="{runtime.tools.python3.path}/python3" -I "{runtime.tools.elf2bin}" --eboot "{runtime.tools.eboot}" --app "{build.path}/{build.project_name}.elf" --flash_mode {build.flash_mode} --flash_freq {build.flash_freq} --flash_size {build.flash_size} --path "{runtime.tools.xtensa-lx106-elf-gcc.path}/bin" --out "{build.path}/{build.project_name}.bin"
 recipe.objcopy.hex.2.pattern="{runtime.tools.python3.path}/python3" -I "{runtime.tools.signing}" --mode sign --privatekey "{build.source.path}/private.key" --bin "{build.path}/{build.project_name}.bin" --out "{build.path}/{build.project_name}.bin.signed" --legacy "{build.path}/{build.project_name}.bin.legacy_sig"
-recipe.objcopy.hex.3.pattern="{runtime.tools.python3.path}/python3" -I "{runtime.tools.sizes}" --elf "{build.path}/{build.project_name}.elf" --path "{runtime.tools.xtensa-lx106-elf-gcc.path}/bin" --mmu "{build.mmuflags}"
+recipe.objcopy.hex.3.pattern="{runtime.tools.python3.path}/python3" -X utf8 -I "{runtime.tools.sizes}" --elf "{build.path}/{build.project_name}.elf" --path "{runtime.tools.xtensa-lx106-elf-gcc.path}/bin" --mmu "{build.mmuflags}"
 
 ## Save hex
 recipe.output.tmp_file={build.project_name}.bin