ChatGPT Plugin for Vim

TODO: Document how to use. In short:

• Set OPENAI_API_KEY environment variable to your OpenAI API Key
• Use plugin Manager of your choice to load the plugin
• Build by going into the plugin directory and running make (requires Go 1.19)
  • TODO: Download pre-built binaries?
• Use the command Chat to start a new chat; type in the bottom of the two windows, and then press Enter in normal mode to send your message.