LXD supports using --profile multiple times, but the plugin does not

[heino]

Description

LXD supports using --profile multiple times:
lxc launch <image> <instance_name> --profile <profile> --profile <profile> ...

The plugin does, however, only support a single profile given as a string.

References

• https://linuxcontainers.org/lxd/docs/master/profiles/#apply-a-profile-to-an-instance
• https://github.com/hashicorp/packer-plugin-lxd/blob/main/builder/lxd/config.go#L33
• https://github.com/hashicorp/packer-plugin-lxd/blob/main/builder/lxd/step_lxd_launch.go#L22