chore: upgrade ehttpc from 0.5.0 to 0.6.0

[zmstone]

En enhancement to auto-recover: #12974

Release version: v/e5.8.1

Summary

ehttpc-0.6.0 introduced zombie connection detection.
see emqx/ehttpc#57

by default, if a http connection is inactive for more than 10s after the last sent request has been expired, it will try to reconnect.

Before the connection is force restarted, an error level log with message force_reconnecting_zombie_http_connection is written.

PR Checklist

Please convert it to a draft if any of the following conditions are not met. Reviewers may skip over until all the items are checked:

• Added tests for the changes
• Added property-based tests for code which performs user input validation
• Changed lines covered in coverage report
• Change log has been added to changes/(ce|ee)/(feat|perf|fix|breaking)-<PR-id>.en.md files
• For internal contributor: there is a jira ticket to track this change
• Created PR to emqx-docs if documentation update is required, or link to a follow-up jira ticket
• Schema changes are backward compatible

Checklist for CI (.github/workflows) changes

• If changed package build workflow, pass this action (manual trigger)
• Change log has been added to changes/ dir for user-facing artifacts update

[emqxqa]

TestExecution