In the current release (both master and devel at least) there is in requirements.yml:
ansible_role-pxe_config v1.2.0
ansible_role-pxe_bootstrap v1.0.0
The former uses json notation for pxe_nodes but latter (boot.py) is not compatible with this. To fix this, please choose the proper version. Either v1.1.0 for pxe_config or tag the latest release of bootstrap with a version number and add that to requirements.yml.
In the current release (both master and devel at least) there is in requirements.yml: ansible_role-pxe_config v1.2.0 ansible_role-pxe_bootstrap v1.0.0
The former uses json notation for pxe_nodes but latter (boot.py) is not compatible with this. To fix this, please choose the proper version. Either v1.1.0 for pxe_config or tag the latest release of bootstrap with a version number and add that to requirements.yml.