ArgumentParser 0.2.0

Additions

• You can now specify default values for array properties of parsable types.
  The default values are overridden if the user provides at least one value
  as part of the command-line arguments.

Changes

• This release of swift-argument-parser requires Swift 5.2.

• Default values for all properties are now written using default initialization
  syntax, including some values that were previously implicit, such as empty
  arrays and false for Boolean flags.

  Migration: Specify default values using typical Swift default value syntax
  to remove the deprecation warnings:

  // old
  @Flag() var verbose: Bool
  // new
  @Flag() var verbose = false

  Important: There is a semantic change for flags with inversions that do
  not have a default value. In previous releases, these flags had a default
  value of false; starting in 0.2.0, these flags will have no default, and
  will therefore be required by the user. Specify a default value of false to
  retain the old behavior.

Fixes

• Options with multiple names now consistently show the first-declared name
  in usage and help screens.
• Default subcommands are indicated in the help screen.
• User errors with options are now shown before positional argument errors,
  eliminating some false negative reports.
• CMake compatibility fixes.