6.0.0: Extended match statement, annotations cleanup

• Added -q command line option which suppresses all diagnostic output
  from the compiler except for errors
  (@thekid)
• Removed support for using curly braces as offset (e.g. $value{0})
  (@thekid)
• Merged PR #92: Add support for explicit octal integer literal notation
  See https://wiki.php.net/rfc/explicit_octal_notation (PHP 8.1)
  (@thekid)
• Merged PR #93: Allow match without expression: match { ... }. See
  https://wiki.php.net/rfc/match_expression_v2#allow_dropping_true
  (@thekid)
• Removed support for legacy XP and Hack language annotations, see #86
  (@thekid)
• Merged PR #96: Enclose blocks where PHP only allows expressions. This
  not only allows fn() => { ... } but also using blocks in match.
  (@thekid)