Automate the release process

[yutaro-sakamoto]

The current release process needs manual operations.
Especially, we need to operate another repository opensourcecobol4j-dockerfilehttps://github.com/[opensourcecobol/opensourcecobol4j-dockerfile](https://github.com/opensourcecobol/opensourcecobol4j-dockerfile) when we release a new Docker image.
We should add a new GitHub Actions workflow to automate these processes.