Added the the content: read and actions: write permissions.

Why actions: write is needed:

1. actions/cache@v5 — Requires write access to save and restore caches
2. actions/setup-go@v6 with cache: true — Uses the cache action internally, so it also needs write access

Current permissions:

• contents: read — To checkout the repository code
• actions: write — To save/restore caches for faster builds

This follows the principle of least privilege: only the permissions needed for the workflow to function. Without actions: write, the cache actions will fail silently or with permission errors.