Works to release version 3.0.0

[Tatsu-syo]

I release version 3.0.0 release candidate version from feature/3.0.0 branch.
I wrote Japanese and English message and help contents.
To release official version, documents update is needed.
If you can help, please do the following.

• Download release candidate version and use it.
• If you found some problems report it.
• Fork source and translate message and help contents.
• Pull request

I plan to release on Feb 13.
If you helps before Feb 12, I integrate it.
Best regards.

[Tatsu-syo]

Now (02/13/2022 JST 14:00), version 3.0.0 is released on GitHub.
Thank you for cooperation.