v11.0.0

Breaking changes:

• Update the signal arg from String to KillSignal (#51, #52 by @JordanMartinez)

  • Exit's BySignal constructor's arg
  • exitH/closeH's signal arg
  • spawnSync's SpawnResult's signal field
  • kill''s signal arg

• Removed safeStdio (#60 by @JordanMartinez)

  Turns out this isn't safe for *Sync functions. AFAIK, this isn't documented
  in Node docs.

New features:

• Added fromKillSignal, fromKillSignal' (#51, #59, #60 by @JordanMartinez)
• Added pidExists (#53 by @JordanMartinez)
• Export toUnsafeChildProcess (#55 by @JordanMartinez)
• Added stdio (#55 by @JordanMartinez)
• Added Eq and Show instance to Shell & KillSignal (#58, #59 by @JordanMartinez)

Bugfixes:

• Fixed exitH's String value for listener (#60 by @JordanMartinez)
• Added missing FFI for execSync' (#60 by @JordanMartinez)
• Update node-streams to v9.0.0 to fix FFI issues (#61 by @JordanMartinez)

Other improvements:

• Fix regression: add ref/unref APIs that were dropped in v10.0.0 (#50 by @JordanMartinez)
• Wrap Unsafe API via ChildProcess in safer way (#54 by @JordanMartinez)
• Update tests to actually throw if invalid state occurs (#60 by @JordanMartinez)