How do you use Composer to manage dependencies in a project?

Composer is a dependency manager for PHP that makes it easy to include and update libraries in a project.

Main steps for use:

1. Create a composer.json file in the root of the project, where you specify the required dependencies and their versions.
2. Run the command composer install to install all dependencies.
3. To update dependencies, use composer update.
4. Include Composer's autoloader in the project via require 'vendor/autoload.php';.

Example composer.json:

{
  "require": {
    "monolog/monolog": "^2.0"
  }
}

This allows centralized management of libraries, simplifies updates, and ensures compatibility.