GitHub deprecated save-state and set-output commands

[yamada-wacul]

Now this action gets a warning:

Warning: The `set-output` command is deprecated and will be disabled soon. Please upgrade to using Environment Files. For more information see: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

Please upgrade to using env files.