2.1.x

Some highlights:

• Speedup of dependency inference, around ~30% faster when used in the Pants codebase.
• New export-codegen goal.
• New pants.backend.python.mixed_interpreter_constraints backend with a py-constraints goal to debug what interpreter constraints are used by code, and py-constraints --summary to get an overview of your repo's interpreter constraints. See Interpreter compatibility and our blog post about this.
• New shorthand for the entry_point field. If you specify the sources field, you can set entry_point=":my_func", and Pants will add the source's module name as the prefix. See package.
• New ./pants help subsystems command to list all configurable option scopes.
• Support for remote caching without remote execution. See Remote Execution.

See here for a detailed change log.