Add CI, update example, dependencies, readme (#228)

* Add CI and update example

1. Add CI build test with GitHub Actions
2. Delete example web target
3. Change example target name to `bitsdojo_window_example`
4. Update example dependencies version

* Update dependencies version

* Update README.md

1. Add badges
2. Optimize markdown syntax
3. Update code block readability

* Add file path to code block

* macOS fixes