Update 13.9 release post for 13.12

Why is this change being made?

This MR is to track changes in the 13.9 release post to account for the new 13.12 milestone.

What is being changed?

This MR updates the files that reference a 14.x release OR May 22, 2021 (specific to removals and deprecations).

TODOS

If your name is in the list below it is because I have identified files you authored that match the criteria above. Please validate the change I have made in the review app, ask for a correction or correct it in this MR and then check your name off the list after confirming the change in the review app. THANK YOU!

@danielgruesso

• “Git default branch name change” - blogs and issues listed, deprecate_default_git_branch.yml

@fzimmer

• “Unicorn will e removed in favor of Puma for GitLab self-managed”, removal-unicorn.yml

• "Geo Foreign Data Wrapper settings removal in 14.0", removal-geo-fdw-settings.yml

• "Legacy storage removal in 14.0", removal_legacy_storage.yml

@joshlambert

• “Helm v2 support”, deprecate_enablement_helm2.yml

• “PostgreSQL 11 support, deprecate_enablement_pg11.yml

@mushakov

• "GitLab OAuth implicit grant deprecation" - I updated the due date but did not change the 14.4 reference in the text, can you validate that is correct or adjust?, ushakov_oathimplicit_deprecation.yml

• “Limit projects returned in GET /groups/:id/“, manage_api_pagination.yml

@ogolowinski

• “Deprecate disk source configuration for GitLab Pages”, deprecation_deprecate_domainsource_configuration_for_gitlab_pages.yml

• "Legacy Feature Flags Deprecation", deprecation_legacy_feature_flags_deprecaion.yml

• "Renewal of the stable Auto Deploy template in Auto DevOps", deprecation_announce_deprecations__major_version_of_autodeployimag.yml

• "Deprecation of release description in the Tags API", deprecation_announce_deprecation_of_release_notes_api.yml

@NicoleSchwartz

• “Deprecations for Dependency Scanning” - may need a blog update too, deprecate_dependency_scanning.yml

• "Removals for License Compliance" - has a blog post you may want to update too, Remove-license-scanning-14-0.yml

@phikai

• “WIP (work in progress) merge requests term deprecated”, Create-code-review-wip-mr-deprecation.yml

@sam.white

• “Container Scanning Engine Clair”, deprecate_clair.yml

@stkerr

• "Fuzz test jobs will fail with allow_failure if vulnerabilities are found", depreate_fuzz_fail_status.yml

@tmccaslin

• “Deprecate and remove secret_detection_default_branch job”, deprecation_remove_secret_detection_default_branch_job_from_secret.yml

• “Deprecating SAST analyzer SAST_GOSEC_CONFIG variable in favor of custom rulesets”, deprecation_deprecating_sast_analyzer_sast_gosec_config_variable_i.yml

• "Pin Static Analysis analyzers and tools to minor versions", pin_static_analysis_analyzers_and_tools_to_the_minor_v.yml

• "Migrate from SAST_DEFAULT_ANALYZERS to SAST_EXCLUDED_ANALYZERS" - I changed from April 22 to June 22 bc of the 14.0 reference, secure_deprecate_sast_default_analyzers.yml

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
• Assign this change to the correct DRI
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the "Maintained by" section in on the page being edited.
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies.
  • If the changes relate to any part of the project other than updates to content and/or data files please make sure to ping @gl-static-site-editor in a comment for a review and merge. For example changes to .gitlab-ci.yml, JavaScript/CSS/Ruby code or the layout files. (this requirement has been removed pending identification of a new DRI for the handbook)