docs: update CONTRIBUTING.md

This commit updates the CONTRIBUTING.md file to include:
- General contribution guidelines.
- More detailed information about the conventional commit format,
   including subject capitalization and line length limits.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: google-labs-jules[bot]

CONTRIBUTING.md

@@ -0,0 +1,42 @@
+# Contributing
+
+We welcome contributions to this project! Please follow these guidelines to ensure a smooth and effective contribution process.
+
+## How to Contribute
+
+- Fork the repository.
+- Create a new branch for your feature or bug fix.
+- Make your changes.
+- Ensure that the tests pass.
+- Submit a pull request with a clear description of your changes.
+
+## Commit Message Format
+
+We use [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) for our commit messages.
+This allows for automated changelog generation and release management.
+
+The commit message format is:
+`type(scope?): subject`
+
+The `type` must be one of the following:
+- `build`: Changes that affect the build system or external dependencies (example scopes: gulp, broccoli, npm)
+- `chore`: Other changes that don't modify src or test files
+- `ci`: Changes to our CI configuration files and scripts (example scopes: Travis, Circle, BrowserStack, SauceLabs)
+- `docs`: Documentation only changes
+- `feat`: A new feature
+- `fix`: A bug fix
+- `perf`: A code change that improves performance
+- `refactor`: A code change that neither fixes a bug nor adds a feature
+- `revert`: Reverts a previous commit
+- `style`: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
+- `test`: Adding missing tests or correcting existing tests
+
+The `scope` is optional and can be used to specify the part of the codebase that is affected by the change.
+The `subject` contains a succinct description of the change:
+- Use the imperative, present tense: "add" not "added" nor "adds".
+- Don't capitalize the first letter.
+- No dot (.) at the end.
+- The subject line must not exceed 50 characters.
+
+The `body` of the commit message is optional and should be used to provide additional context.
+- The body should be wrapped at 72 characters.