v2.0.0

This major release makes all Python code synchronous (asynchronous code was mainly for logging, now handled by C++ spines). It also ships binary releases of the pi3hat spine that can be directly used on the robots, improves the MPC and PPO agents, and cleans up legacy dependencies.

Thanks to @boragokbakan and @pgraverdy for contributing to this release 👍

Added

• PPO balancer: Allow custom training path
• PPO balancer: Allow re-training with the same policy name
• PPO balancer: Low-pass filter action before acceleration clamping
• PPO balancer: Update reward to penalize commanded accelerations
• UpkieGroundVelocity: Augment observation with previous command
• agents: Closed-loop model predictive control
• envs: Allow custom initial base velocity in Bullet config
• examples: Closed-loop model predictive control
• spines: Build and export the pi3hat spine binary in continuous integration, by @pgraverdy
• spines: --version flag for all spine binaries

Changed

• MPC balancer: Remove asyncio logic
• PPO balancer: Remove asyncio logic
• Pink balancer: Remove asyncio logic
• Wheel balancer: Remove asyncio logic
• envs: Move reset state sampling to InitRandomization class
• spines: Add _spine suffix to binary names, e.g. pi3hat_spine
• spines: Allow pi3hat spine to run without joystick if user validates

Fixed

• Make Makefile date command more portable, by @boragokbakan
• PPO balancer: Correct save frequency during training
• PPO balancer: Run policy deterministically after training
• envs: Merge default and runtime configuration dictionaries

Removed

• Breaking: async_step function and asyncio logic
• Breaking: pi32_config as 64-bit is the new default
• Breaking: upkie.utils.log_path submodule and its utility function
• Dependency on mpacklog.cpp (already in Vulp)
• Dependency on mpacklog.py