Hey @eturok might be late to the party but you can try updating the github actions to include graphviz installation step before calling fastai CI. Here is what worked for me
name: CI
on: [workflow_dispatch, pull_request, push]
jobs:
test:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- name: Setup Graphviz
uses: ts-graphviz/setup-graphviz@v1
- uses: fastai/workflows/nbdev-ci@master