Release 0.6.0

What's Changed

• Adds multi-training backend support by @edbeeching in #111
• feat(sb3): also track reward in tensorboard by @visuallization in #113
• feat(multi discrete action spaces): added support for multi discrete action spaces by @visuallization and @Ivan-267 in #110
• Fixes clean_rl_example.py default env path and related CUSTOM_ENV documentation section by @Ivan-267 in #116
• Update setup.cfg to fix sb3 not training after installing godot-rl by @Ivan-267 in #120
• Update CUSTOM_ENV.md - Small spelling correction by @Ivan-267 in #122
• Adds multiple env support to the SB3 wrapper by @edbeeching in #123
• Feature: experiment_dir + experiment_name by @visuallization in #126
• Experiment name typo correction by @Ivan-267 in #131
• chore(docs): added short entry regarding training statistics and tensorboard by @visuallization in #128
• Feature/hp tuning by @visuallization in #130
• Updates support of sb3 to latest version by @edbeeching in #134
• Adds resuming and saving model to sb3 example by @Ivan-267 in #135
• Update ADV_STABLE_BASELINES_3.md by @Ivan-267 in #136

Full Changelog: v0.5.0...v0.6.0