Trying to display outdated HACS components with flex-table-card


I’m trying to display information about outdated HACS components. For this, I have defined some sensors (basically following this approach) which provide the outdated repositories. Thus, with Development Tools/Template, the statement {{ (state_attr('binary_sensor.hacs_update_issues', 'status')).repositories }} results in the following output:

[{'name': 'FL550/dwd_weather', 'display_name': 'Deutscher Wetterdienst', 'installed_version': 'v1.2.1', 'available_version': 'v1.2.2'}, {'name': 'briis/weatherbit', 'display_name': 'Weatherbit Weather Forecast for Home Assistant', 'installed_version': 'v0.34', 'available_version': 'v0.34.1'}]

I’m then trying to use the following code for the UI part:

type: 'custom:auto-entities'
  type: 'custom:flex-table-card'
  title: Pending HACS updates
    - name: Component
      data: display_name
    - name: Current version
      data: installed_version
    - name: Latest version
      data: available_version
    method: attribute
    attribute: display_name
  template: >
    {{ (state_attr('binary_sensor.hacs_update_issues', 'status')).repositories }}

However, no rows are shown. The same is true for the following template I tried.

    {%- for repository in (state_attr('binary_sensor.hacs_update_issues', 'status')).repositories -%}
      {{ repository}},
    {%- endfor -%} 

Is what I’m doing possible at all with flex-table-card? Thanks in advance…