Feat: Add npm badges to README.md

[ioncakephper]

Description

This issue serves as a reminder to enhance the README.md file by adding relevant npm badges. These badges provide quick visual information about the package's status on npmjs.com.

Proposed Badges

Consider adding the following badges:

• npm version: Displays the latest published version of the package.
  Example: ![npm version](https://img.shields.io/npm/v/your-package-name.svg)
• npm downloads: Shows the number of downloads (e.g., monthly, weekly, total).
  Example: ![npm downloads](https://img.shields.io/npm/dm/your-package-name.svg)

Acceptance Criteria

• The README.md file is updated to include at least the "npm version" badge.
• The badges are correctly displayed and link to the appropriate npmjs.com page for the php-theme-gen package.
• The new badges are integrated aesthetically with the existing badges in the README.md.