[ironic] retirement of old bugfix branches

Hello everyone!

We're going to remove old bugfix branches in the next few weeks, all bugfix branches that are older than 6 months are officially EoL. This includes: - for ironic bugfix/18.0 bugfix/18.1 bugfix/19.0 bugfix/20.2 bugfix/21.0 bugfix/21.2 - for ironic-inspector bugfix/10.7 bugfix/10.9 bugfix/10.12 bugfix/11.0 bugfix/11.2 -for ironic-python-agent bugfix/8.0 bugfix/8.1 bugfix/8.3 bugfix/8.6 bugfix/9.0 bugfix/9.2

Thanks!

Ciao

Riccardo