Bump Ignition distribution to Fortress

[diegoferigo]

• Roadmap

---

• Update CMake logic
  • [x] Add the new version in FindIgnitionDistribution.cmake
  • [x] Create a new ImportTargets<>.cmake
  • [x] Update SUPPORTED_IGNITION_DISTRIBUTIONS
• Update CI to:
  • [x] Build and test gym-ignition against Fortress
  • [x] Build and upload wheels by default against Fortress
  • [x] Build docker images with Fortress
• [x] Check that all documentation is updated
• [x] Check that building the wheel locally succeeds by passing custom Dome flag to pip / setup.py (even if not supported officially)
• [ ] Mark the new workflow Build and Test (<New Ignition Distribution>) check as Required in the branches setting

[diegoferigo]

Trying the example panda_pick_and_place.py, there is a weird behavior.

The scripts executes the simulation in the same thread of the Python environment, and open a new process with the GUI. In the beginning, everything seems working fine: the world is populated, the custom plugins are inserted, and the manipulator moves as expected. However, the first time the manipulator grasps the cube, the GUI stops being updated (or, it is extremely slow). Though, I can see the server running and printing messages in the terminal.

Not sure what's going on here, seems a behavior similar to https://github.com/ignitionrobotics/ign-gazebo/issues/997. Also in my example, the contact system is enabled and the GUI get stuck as soon as a contact is detected.