release_2.1.0rc0

New Features

• Add export-codegen goal (#11107)
• Add ./pants py-constraints --summary for project
  overview (#11099)
• Add ./pants help subsystems (#11088)
• Improve performance of dependency inference (#11094)

User API Changes

• Change default for --pants-distdir-legacy-paths and
  deprecate it (#11096)
• Clarify that process cache namespacing works for all runners
  (#11095)
• Deprecate target names containing slashes and colons (#11115)

Plugin API Changes

• Rename SourcesSnapshot to SpecsSnapshot
  (#11114)

Bugfixes

• Fix logs for test, lint,
  fmt, and typecheck to always print, even
  if cached (#11111)
• Fix pytest.pex leaking into coverage data (#11110)
• Fix --pex-verbosity to work with the interpreter
  selection PEX (#11108)
• Fix !! transitive excludes when used multiple times in
  a repo (#11103)
• Fix setup_py.with_provides() to respect the
  :func entry-point shorthand (#11093)
• Include a host fingerprint in pantsd's identity (#11092)

Documentation

• Improve error message for invalid unions in Get()s (#11102)