Update CHANGELOG.md for 12.8.0

[ci skip]

changelogs/unreleased/196843-remove-feature-flag.yml

----
-title: Container Registry tag expiration policy settings
-merge_request: 25123
-author:
-type: added

changelogs/unreleased/196858-cleanup-temporary-index-at-services-table-on-project_id.yml

----
-title: Remove temporary index at services on project_id
-merge_request: 24263
-author:
-type: removed

changelogs/unreleased/196861-improve-pipelines-copy.yml

----
-title: Update pipeline status copy in deploy footer
-merge_request: 23199
-author:
-type: changed

changelogs/unreleased/196881-reverse-actions-for-status-update.yml

----
-title: Reverse actions for resolve/ignore Sentry issue
-merge_request: 23516
-author:
-type: added

changelogs/unreleased/197292-support-require_password_to_approve-in-post-projects-id-approvals-.yml

----
-title: Support require_password_to_approve in project merge request approvals API
-merge_request: 24016
-author:
-type: added

changelogs/unreleased/197309-milestone-in-issue-boards-list-not-cropped-when-longer-than-board-.yml

----
-title: Allow long milestone titles on board lists to be truncated
-merge_request:
-author:
-type: fixed

changelogs/unreleased/197311-board-list-wip-limit-distorted-when-board-list-is-scoped-to-an-ass.yml

----
-title: Fix issue count wrapping on board list
-merge_request:
-author:
-type: fixed

changelogs/unreleased/197371-show-notification-on-related-error-close.yml

----
-title: Close related GitLab issue on Sentry error resolve
-merge_request: 23610
-author:
-type: added

changelogs/unreleased/197412.yml

----
-title: Track usage of merge request file header buttons
-merge_request:
-author: Oregand
-type: other

changelogs/unreleased/197500-edit-and-web-ide-look-like-segmented-control-in-file-header.yml

----
-title: Remove button group for edit and web ide in file header
-merge_request: 23291
-author:
-type: other

changelogs/unreleased/197879-add-relative-time-ranges-to-datepicker.yml

----
-title: Allow for relative time ranges in metrics dashboard URLs
-merge_request: 23765
-author:
-type: added

changelogs/unreleased/197894.yml

----
-title: MVC for assignees avatar dissapearing when opening issue sidebar in board
-merge_request:
-author: Oregand
-type: fixed

changelogs/unreleased/197926-initial-package-detail-title.yml

----
-title: Updated package details page header to begin updating the page design.
-merge_request: 24055
-author:
-type: added

changelogs/unreleased/197932-add-package-tags-display-to-package-list-page.yml

----
-title: Displays package tags next to the name on the new package list page
-merge_request: 23675
-author:
-type: added

changelogs/unreleased/197973-staged-and-unstaged-modification-tooltip-for-file-with-staged-chan.yml

----
-title: Remove unstaged and staged modification tooltip
-merge_request: 23847
-author:
-type: fixed

changelogs/unreleased/198009-ms-teams-notification-message-improved.yml

----
-title: Improve message UI on Microsoft Teams notification
-merge_request: 23385
-author: Takuya Noguchi
-type: fixed

changelogs/unreleased/198042-argumenterror-wrong-number-of-arguments-given-1-expected-2.yml

----
-title: Fixes AutoMergeProcessWorker failing when merge train service is not available
-  for a merge request
-merge_request: 23407
-author:
-type: fixed

changelogs/unreleased/198313-remove-code-hotspots-tables.yml

----
-title: Remove unused Code Hotspots database tables
-merge_request: 23590
-author:
-type: other

changelogs/unreleased/198411-jira-http-error.yml

----
-title: Fix JIRA::HTTPError initialize parameter
-merge_request: 24060
-author:
-type: fixed

changelogs/unreleased/198411-more-verbose-jira-error-logs.yml

----
-title: More verbose JiraService error logs
-merge_request: 23688
-author:
-type: other