Updated models and new options

• Updated to make new models available
• Changed default model to gpt-3.5-turbo-1106
• Added --commit-msg-path flag: This is used to check if a Merge or Revert etc commit message already exists, if it does we just return unchanged.
• Added --context-lines which allows you to increase the amount of surrounding lines around changes to give more detail

New models and refinements

A few small improvements:

• Add new models and change default to gpt-3.5-turbo
• Update to go 1.20
• Use the more common OPENAI_API_KEY env variable name
• Exit early if there are no changes (rather than just imagining a commit msg)

Initial release

Notable changes:

• Actually did a release with ready-to-go binaries
• Added a --version flag for debugging installs
• Added a --git-message-template flag to override the default template AND configured commit.template