Add Go Interview Practice to Learning Resources

Addresses issue #2816 by adding a new Learning Resources section to the README
with the Go Interview Practice platform.

**Added:**
- New "Learning Resources" section with structured table format
- Go Interview Practice platform: Interactive learning with 4 hands-on Echo challenges
- Covers routing, middleware, validation, and authentication
- No setup required - developers can practice Echo immediately

**Context:**
- Similar learning resource has been successfully added to Gin and Fiber frameworks
- Provides practical, hands-on learning experience for Echo developers
- Complements existing documentation with interactive challenges

The resource includes:
- GitHub repository: https://github.com/RezaSi/go-interview-practice
- Live platform: https://app.gointerview.dev/packages/echo
- Specific Echo challenges covering core framework concepts

This addition helps developers learn Echo through practical exercises and
supports the framework's adoption by providing accessible learning materials.

Fixes #2816

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -118,6 +118,12 @@ of middlewares in this list.
 
 Please send a PR to add your own library here.
 
+## Learning Resources
+
+| Resource | Description |
+|----------|-------------|
+| [Go Interview Practice](https://github.com/RezaSi/go-interview-practice) | Interactive platform with hands-on Echo challenges covering routing, middleware, validation, and authentication. Practice Echo development without any setup. |
+
 ## Contribute
 
 **Use issues for everything**