CompilerGym v0.2.3

This release brings in deprecating changes to the core env.step() routine, and lays the groundwork for enabling new types of compiler optimizations to be exposed through CompilerGym. Many thanks to code contributors: @mostafaelhoushi, @sogartar, @KyleHerndon, @uduse, @parthchadha, and @xtremey!

Highlights of this release include:

• Added a new TextSizeInBytes observation space for LLVM (#575).

• Added a new PPO leaderboard entry (#580). Thanks @xtremey!

• Fixed a bug in which temporary directories created by the LLVM environment were not cleaned up (#592).
• [Backend] The function createAndRunCompilerGymService now returns an int, which is the exit return code (#592).
• Improvements to the examples documentation (#548) and FAQ (#586)

Deprecations and breaking changes:

• CompilerEnv.step no longer accepts a list of actions (#627). A new method, CompilerEnv.multistep provides this functionality. This is to provide compatibility with environments whose action spaces are lists. To update your code, replace any calls to env.step() which take a list of actions to use env.multistep(). Thanks @sogartar!
• The arguments observations and rewards to step() have been renamed observation_spaces and reward_spaces, respectively (#627).
• Reward.id has been renamed Reward.name (#565, #612). Thanks @parthchadha!

• The backend protocol buffer schema has been updated to natively support more types of observation and action, and to support nested spaces (#531). Thanks @sogartar!

Full Changelog: v0.2.2...v0.2.3