release: 4.7.0 (#5546)

* docs: update MAINTAINING

* refactor: use branch name in release-prep

This makes a minor improvement to the `release-prep.sh` script to grab
the version to update to from the branch name.

* chore(release): bump version to 4.7.0

* fixup: bump version

* docs: use latest instead of version

* fixup: bump Chart version

* chore: update CHANGELOG

* chore: add license to test package.json

* chore: bump @coder/logging to 3.0.0

* fix: change level to Warn