Error: Failed to initialize build "arm-image"
The builder arm-image is unknown by Packer, and is likely part of a plugin that
is not installed.
You may find the needed plugin along with installation instructions documented
on the Packer integrations page.
https://developer.hashicorp.com/packer/integrations?filter=arm
Regressing to 1.10.3 resolves the problem.
The breaking change is documented here: https://github.com/hashicorp/packer/releases/tag/v1.11.0