message: workflows: add docs check again
  This got lost when moving from Jenkins to travis.
diff: @@ -56,7 +56,7 @@ jobs:
  run: ./build/release/src/backend/test/unit_tests_backend
  ubuntu18-check-style:
  - name: ubuntu-18.04 (check style)
  + name: ubuntu-18.04 (check style and docs)
  runs-on: ubuntu-18.04
  container: mavsdk/mavsdk-ubuntu-18.04
  steps:
  @@ -65,6 +65,8 @@ jobs:
  submodules: recursive
  - name: check style
  run: ./tools/fix_style.sh .
  + - name: check docs
  + run: tools/generate_docs.sh
  px4-sitl:
  name: PX4 SITL (ubuntu-18.04)
  