fix: Rollback log format configuration

[sawadashota]

Proposed changes

Rollback log format configuration to log.format from log.formatter if unintentional. (because I couldn't find this change at CHANGELOG.md)
Environment variable is not changed because it remains LOG_FORMAT.

ref #155

Checklist

• I have read the contributing guidelines
• I have read the security policy
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security vulnerability, I
  confirm that I got green light (please contact
  security@ory.sh) from the maintainers to push
  the changes.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation within the code base (if appropriate)

Further comments

[sawadashota]

@aeneasr Could you review this PR?
If my proposal is rejected, I think LOG_FORMAT should be changed to LOG_FORMATTER.

[aeneasr]

Sorry, I forgot this. Yup looks good!

[sawadashota]

Thank you!

[aeneasr]

v0.0.132