fix(compatibility): resolve deprecated PHP warnings and update docs

[danieldpl]

fix(compatibility): resolve deprecated PHP warnings

• Replaced deprecated function calls and adjusted code for compatibility with PHP 8.x+.
• Fixed warnings related to optional parameters and null types.
• Refactored equipJobsToArray() method for clarity and compliance.
• Removed unnecessary indentation and trailing whitespace.

docs(readme): updated README with installation guide and PHP requirements

• Added a basic installation guide to README.md.
• Updated minimum PHP version to 7.0 due to usage of the null coalescing operator (??).
• Improved formatting and documentation consistency.

BREAKING CHANGE: Requires PHP >= 7.0.