Release 2.1.0

• Fixed #37
• Added latest Gerber spec file revision 2023.08 to documentation.
• Added command line interface for PyGerber 2D rendering.
• Added Gerber X3/X2 language server which can be acquired with
  pip install pygerber[language-server]. Currently server capabilities include hover
  messages with Gerber reference cited and minimal amount of suggestions. We are
  planning to further extend this server in future releases.
• Added is-language-server-available CLI command for checking if
  pygerber[language-sever] is available.
• Added support for arc region boundaries (#61).
• Added warning messages whenever zero surface flash is created.
• Improved documentation for many of supported Gerber commands. This documentation is
  used by language server to provide specification reference.
• Refactored tokenizer implementation, as a result #67 was fixed and #64 is no longer an
  issue in some cases.