Update CHANGELOG.md for 12.3.0

[ci skip]

changelogs/unreleased/62055-find-file-links-encoding.yml

----
-title: Fix encoding of special characters in "Find File"
-merge_request: 31311
-author: Jan Beckmann
-type: fixed

changelogs/unreleased/62122-hide-resolve-thread-button-from-guest.yml

----
-title: Hide resolve thread button from guest
-merge_request: 32859
-author:
-type: changed

changelogs/unreleased/62284-follow-up-from-resolve-api-to-get-all-project-group-members-returns-duplicates.yml

----
-title: Uses projects_authorizations.access_level in MembersFinder
-merge_request: 28887
-author: Jacopo Beschi @jacopo-beschi
-type: fixed

changelogs/unreleased/62322-add-optional-id-to-label-api-put-delete-pd.yml

----
-title: Add optional label_id parameter to label API for PUT and DELETE
-merge_request: 31804
-author:
-type: changed

changelogs/unreleased/62373-badge-counter-very-low-contrast-between-foreground-and-background-c.yml

----
-title: 'Resolve Badge counter: Very low contrast between foreground and background
-  colors'
-merge_request: 31922
-author:
-type: other

changelogs/unreleased/62402-milestone-release-be.yml

----
-title: Allow milestones to be associated with a release (backend)
-merge_request: 30816
-author:
-type: added

changelogs/unreleased/62591-fix-milestone-due-date-today-wording.yml

----
-title: Fix wording on milestone due date when milestone is due today
-merge_request: 32096
-author:
-type: changed

changelogs/unreleased/62673-clean-note-app-tests.yml

----
-title: make test of note app with comments disabled dry
-merge_request: 32383
-author: Romain Maneschi
-type: other

changelogs/unreleased/63262-notes-are-persisted-with-the-user-s-locale.yml

----
-title: Do not translate system notes into author's language
-merge_request: 32264
-author:
-type: fixed

changelogs/unreleased/63502-encrypt-deploy-token.yml

----
-title: Encrypt existing and new deploy tokens
-merge_request: 30679
-author:
-type: other

changelogs/unreleased/63905-discussion-expand-collapse-button-is-only-clickable-on-one-side.yml

----
-title: All of discussion expand/collapse button is clickable
-merge_request: 31730
-author:
-type: fixed

changelogs/unreleased/64009-show-a-meaningful-error-message-when-due-quick_actions-command-fail.yml

----
-title: Show meaningful message on /due quick action with invalid date
-merge_request: 32349
-author: Jacopo Beschi @jacopo-beschi
-type: changed

changelogs/unreleased/64122-documentation-lacks-how-to-enable-project-snippets.yml

----
-title: Mention in docs how to disable project snippets
-merge_request: 32391
-author: Jacopo Beschi @jacopo-beschi
-type: other

changelogs/unreleased/64213-not_filtering.yml

----
-title: Add not param to Issues API endpoint
-merge_request: 16748
-author:
-type: added

changelogs/unreleased/64269-pipeline-api-fails-with-401.yml

----
-title: Read pipelines from public projects through API without an access token
-merge_request: 31816
-author:
-type: fixed

changelogs/unreleased/64383-pattern-matching-with-variables-causes-gitlabs-ci-lint-to-throw-500.yml

----
-title: Fix 500 errors caused by pattern matching with variables in CI Lint
-merge_request: 31719
-author:
-type: fixed

changelogs/unreleased/64385-charts-scroll-handle-icon-has-disappeared.yml

----
-title: fix charts scroll handle icon to use gitlab svg
-merge_request: 31825
-author:
-type: fixed

changelogs/unreleased/64630-add-warning-to-pages-domains-that-obtaining-deploying-ssl-certifica.yml

----
-title: Add warning to pages domains that obtaining/deploying SSL certificates through
-  Let's Encrypt can take some time
-merge_request: 31765
-author:
-type: other

changelogs/unreleased/64677-delete-directory-webide.yml

----
-title: Fixed removing directories in Web IDE
-merge_request: 31727
-author:
-type: fixed

changelogs/unreleased/64764-fix-serverless-layout.yml

----
-title: Fix serverless entry page layout
-merge_request: 32029
-author:
-type: fixed