Add latest changes from gitlab-org/gitlab@12-8-stable-ee

changelogs/unreleased/update-graphicsmagick-to-1-3-34.yml

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-title: Update GraphicsMagick from 1.3.33 to 1.3.34
-merge_request: 24225
-author: Takuya Noguchi
-type: security

changelogs/unreleased/update-handlebarsjs.yml

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-title: Update handlebars to remove issues from dependency dashboard
-merge_request:
-author:
-type: security

changelogs/unreleased/update_cluster-applications_v0-7-0.yml

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-title: Updated cluster-applications to v0.7.0
-merge_request: 24754
-author:
-type: changed

changelogs/unreleased/weimeng-upgrade-omniauth-github.yml

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-title: Upgrade omniauth-github gem to fix GitHub API deprecation notice
-merge_request: 24928
-author:
-type: fixed

changelogs/unreleased/xanf-prohibit-outer-forks.yml

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-title: Added "Prohibit outer fork" setting for Group SAML
-merge_request: 25246
-author:
-type: added

changelogs/unreleased/youtrack-issue-pattern.yml

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-title: Avoid autolinking YouTrack issue numbers followed by letters
-merge_request: 24770
-author: Konrad Borowski
-type: fixed