[v2.1.2] Hotfix for regional private endpoint DNS zones

This PR includes an important hotfix for the regional private endpoint DNS zones to ensure the correct zones are created for the following services:

• azure_backup
• azure_site_recovery

IMPORTANT:
Please note that this hotfix may result in the removal of existing (invalid) DNS zones, and addition of new (correctly configured) DNS zones.
If you would like to keep the existing DNS zones, these can be added to your configuration using the configure_connectivity_resources.settings.dns.config.private_dns_zones input variable.

What's Changed

• Fix configure_management_resources value in Wiki example by @krowlandson in #422
• Patch regional private endpoint DNS zones by @krowlandson in #423
• Update docs for release v2.1.2 by @krowlandson in #424

Full Changelog: v2.1.1...v2.1.2