v0.2.0

Add cobra for command line processing (#1)

* Add `commit` and `init` commands for generating Git commit messages with AI

- Implemented `commit` command to suggest and apply Git commit messages based on staged changes.
- Introduced `init` command for configuring the commit message provider.
- Removed main logic from the previous `main.go` and relocated it to the appropriate command structure.
- Integrated configuration management using `viper` for handling provider settings.
- Improve error handling in CreateCommitMessage and restructure imports.