feat: return error cause in http response from gateway

[wenfengwang]

What problem does this PR solve?

Issue Number: #167

Problem Summary

This problem caused by cloudevents go-sdk, and it was fixed in cloudevents/sdk-go#785

What is changed and how does it work?

upgrade SDK version to v2.11.0, and format output of vsctl event put

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

Before:

After:

• No code

[codecov]

Codecov Report

Merging #242 (3438988) into main (3f72df1) will increase coverage by 0.03%.
The diff coverage is 40.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #242      +/-   ##
==========================================
+ Coverage   63.50%   63.54%   +0.03%     
==========================================
  Files         118      118              
  Lines       11353    11353              
==========================================
+ Hits         7210     7214       +4     
+ Misses       3589     3586       -3     
+ Partials      554      553       -1     

Impacted Files	Coverage Δ
internal/gateway/gateway.go	69.00% <40.00%> (ø)
internal/timer/timingwheel/timingwheel.go	79.02% <0.00%> (+0.88%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update fe92767...3438988. Read the comment docs.

[ifplusor]

I think this PR can not solve #167, it is only a little part.