Updated dependencies and cleaned code

[javiermarinros]

Bumped required minimum PHP version to 8.2
Added support for PhpStan static analysis and fixed the found issues

[Copilot]

Pull Request Overview

This PR updates dependencies and cleans code by bumping the PHP version to 8.2, updating the Symfony HTTP client version, adding support for PhpStan static analysis, and refactoring various code sections to use modern PHP syntax.

• Updated static analysis configuration with PhpStan.
• Refactored string concatenation to interpolation and updated array syntax.
• Bumped PHP and dependency versions in composer.json and updated documentation.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
phpstan.neon	Adds a PhpStan configuration file with analysis parameters.
lib/Service/UpdateService.php	Refactors HTTP request URL construction and updates parameter type hints.
lib/Service/ProfileService.php	Standardizes URL interpolation for HTTP requests.
lib/Model/Update.php	Updates array syntax and adjusts docblocks to acknowledge nullable types.
lib/Model/Schedule.php	Refactors constructors and array initializations with modern syntax.
lib/Http/Client.php	Simplifies the HTTP client method by directly returning the response array.
lib/Auth/AuthorizationTokenInterface.php	Adds a return type hint for the access token.
lib/Auth/AuthorizationToken.php	Makes minor docblock adjustments.
composer.json	Bumps PHP version, updates Symfony HTTP client version, and adds PhpStan to dev requirements.
README.md	Updates PHP version prerequisite in the documentation.