chore(workflows): remove synchronize trigger for label-schema

[harrydt]

Summary

Currently, a Slack notification is sent to #gateway-schema-change-feed for every commit in a PR that has the label schema-change-noteworthy.
From the Koko side, we're only interested in the change as a whole (PR level). This change aims to reduce the duplicate messages and make it easier to keep track of gateway schema changes.

Checklist

• The Pull Request has tests
• A changelog file has been created under changelog/unreleased/kong or skip-changelog label added on PR if changelog is unnecessary. README.md
• There is a user-facing docs PR against https://github.com/Kong/docs.konghq.com - PUT DOCS PR HERE

Issue reference

Fix #[issue number]

[zhongweiy]

Looks good to me. I just want to confirm is it because we usually do the rebase for several times when the build failed, which is a synchronize event and generate too much message?

[harrydt]

Looks good to me. I just want to confirm is it because we usually do the rebase for several times when the build failed, which is a synchronize event and generate too much message?

Yea, and also if new commits were pushed to head branch (the branch of the PR).
That's my understanding based on https://docs.github.com/en/webhooks/webhook-events-and-payloads?actionType=synchronize#pull_request

A pull request's head branch was updated. For example, the head branch was updated from the base branch or new commits were pushed to the head branch.

In #gateway-schema-change-feed we usually get a notification for every new commit on the same PR.

[team-gateway-bot]

Successfully created cherry-pick PR for master:

• https://github.com/kong/kong-ee/pull/8709