Update CHANGELOG.md for 9.3.0

[ci skip]

changelogs/unreleased/zj-read-registry-pat.yml

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-title: Allow pulling of container images using personal access tokens
-merge_request: 11845
-author:

changelogs/unreleased/zj-realtime-env-list.yml

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-title: Make environment table realtime
-merge_request: 11333
-author:

changelogs/unreleased/zj-sort-env-folders.yml

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-title: Sort folder for environments
-merge_request:
-author: