docs: Add status badges to README

This commit adds GitHub Actions and Ruff status badges to the `README.md` to provide a quick, visible status of the project's CI and code quality.

Author: RandomProgramm3r

README.md

@@ -1,5 +1,8 @@
 # Promo Code API
 
+[![Linting](https://github.com/RandomProgramm3r/Promo-Code-API/actions/workflows/linting.yml/badge.svg)](https://github.com/RandomProgramm3r/Promo-Code-API/actions)
+[![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json)](https://github.com/astral-sh/ruff)
+
 The application provides an HTTP API for companies and end-users, is integrated with an external anti-fraud service, and uses PostgreSQL and Redis for data storage and caching.