Ci/check labels v2

[macintoshpie]

Any background context you want to provide?

See issue

What does this PR do?

• add CI requirements for PR labels
• update the changelog script to look at PRs instead of issues for changes (see #417 for more info)

How should this be manually tested?

feel free to add/remove labels to this PR. Try running the changelog script

What are the relevant tickets?

405

Screenshots (if appropriate)

[macintoshpie]

@JieXiong9119 things should be good now, and up to date with develop-v3's files