v5.0.0

Breaking changes:

• getResult's childProcess label now stores an UnsafeChildProcess (previously ChildProcess)
• getResult's stdin/stdout/stderr conveience functions are now wrapped in Maybe

New Features:

• Allows stdio values to be configurable

  Previously, a stdio value of [ 'pipe', 'pipe', 'pipe', 'ipc' ] <> appendStdio was used.
  However, this caused issues when piping a parent process' stdin into the child process' stdin,
  such that the child would never terminate when the user presses Ctrl+D. By making stdio
  configurable, one can use inherit instead, which resolves this issue.

  Note: execa's stdio always specifies the first 4 values in the stdio array whereas
  execaSync only specifies the first 3 values.