[v2.1.1] Hotfix for `custom_landing_zones`

What's Changed

This PR includes the following updates:

• Wiki updates by @krowlandson in #399
• Feature Request - Custom Setting Support for vnet peerings by @matt-FFFFFF in #401
• Add option to add identity block to an Automation Account by @matt-FFFFFF in #407
• Update Wiki docs for vwan by @krowlandson in #414
• Update validation for custom_landing_zones by @krowlandson in #416
• Update for release v2.1.1 by @krowlandson in #417

These are being bundled in a patch release as they are all no-impact changes to existing users of the module.

Full Changelog: v2.1.0...v2.1.1