docs: update PR template

[maxekman]

Summary

Focus the PR template or what has changed instead of what the CI can check.

Type of change

• Bug fix
• New feature
• Breaking change
• Refactor / chore
• Documentation

[github-actions]

TCK Compliance Results

📊 COMPREHENSIVE TEST RESULTS SUMMARY
================================================================================

🔴 Mandatory Tests:           ✅ PASSED (p:83/f:0/x:0/e:0/s:32)
🔄 Capability Tests:          ✅ PASSED (p:20/f:0/x:1/e:0/s:54)
🚀 Transport Equivalence:     ✅ PASSED (p:0/f:0/x:0/e:0/s:16)
🛡️  Quality Tests:             ✅ PASSED (p:14/f:0/x:0/e:0/s:0)
🎨 Feature Tests:             ✅ PASSED (p:14/f:0/x:1/e:0/s:1)

🎉 A2A COMPLIANCE: ✅ PASSED
Your implementation meets A2A specification requirements!
🔄 CAPABILITY HONESTY: ✅ EXCELLENT
All declared capabilities work correctly!
🛡️  PRODUCTION QUALITY: ✅ HIGH
Implementation is robust and production-ready!
🎨 FEATURE COMPLETENESS: ✅ COMPREHENSIVE
Implementation includes valuable optional features!

🏆 OUTSTANDING A2A IMPLEMENTATION!

================================================================================

========================================
TCK run complete.
Stopping server (PID 2816)...

07:29:04.816 [notice] SIGTERM received - shutting down