Jobs running as root even if root: true has not been specified

The lpci documentation [1] says that the default value for the 'root' option is 'false', which means that by default jobs should run under the unprivileged _lpci user. However lpci behaves as if the default was root: true. To reproduce prepare a branch with this .launchpad.yaml:

pipeline:
  - pre_commit

jobs:
  pre_commit:
    series: focal
    architectures: amd64
    run-before: |
      set -x
      id
      whoami
    run: |
      set -x
      id
      whoami

and check the job output. As of today this is:

Running command for the job...
Running ['bash', '--noprofile', '--norc', '-ec', 'set -x\nid\nwhoami\n']
:: + id
:: uid=0(root) gid=0(root) groups=0(root)
:: + whoami
:: root
Running command for the job...
Running ['bash', '--noprofile', '--norc', '-ec', 'set -x\nid\nwhoami\n']
:: + id
:: uid=0(root) gid=0(root) groups=0(root)
:: + whoami
:: root

This is also reproducible by running lpci locally.

Explicitly setting `root: false` makes the job run under _lpci user, as expected.

[1] https://lpci.readthedocs.io/en/latest/configuration.html