We have added the ability to export and import the relation between
Board and Milestones.

Currently our Milestone model has some predefined instances that are not
actually persisted to the database (only their ID is persisted on the
related model).

We don't want to import these as actual relations in the database as
their predefined IDs imply some additional functionality in the system -
which is lost if they are imported as a new record.

For now, ignore these records on import as we do not have a clear way to
handle them - but we still need to import the user generated milestones.

We want to be able to export the milestones on Boards for groups as
well.

Prior to this change, adding `:milestone` to the export config file
would result in an error when the `serialize_hash` method was called on
the MilestoneStruct, which is used for predefined, system wide
milestones.

Add this method to the struct so that it responds to the needed
interface and add `:milestone` to the config file for export.

Convert branches-select component to jest

Closes #204800

See merge request gitlab-org/gitlab!25954

Update the code review guide to take the Merge Results in account

See merge request gitlab-org/gitlab!25449

Update the docs monthly release process

See merge request gitlab-org/gitlab!25977

Use Workhorse acceleration on Project Import file upload

See merge request gitlab-org/gitlab!25361

This is related to API endpoints only, UI endpoints
(Import::GitlabProjectsController) will be accelerated
in the next, separate MR.
Since we are touching an existing API, we should deploy it gradually.
So this MR will support both accelerated and "vanilla"
uploads for the endpoint.

GraphQL fields should generally be nullable

See merge request gitlab-org/gitlab!26001

Add debugging to see output when profiler_spec fails

See merge request gitlab-org/gitlab!26015

Fix lack of Oxford comma in some documentation

See merge request gitlab-org/gitlab!26039

Apply suggestion to doc/ci/merge_request_pipelines/pipelines_for_merged_results/merge_trains/index.md

Added pipeline chart details

Closes #34905

See merge request gitlab-org/gitlab!25833

For https://gitlab.com/gitlab-org/gitlab/issues/34905, added chart details

Remove dead code: Label#template?

See merge request gitlab-org/gitlab!25976

Docs: Update API code blocks

See merge request gitlab-org/gitlab!26017

Docs: Update more API code blocks

See merge request gitlab-org/gitlab!26019

Docs: Update API code blocks

See merge request gitlab-org/gitlab!26018

Docs: Update API code blocks to use 'plaintext'

See merge request gitlab-org/gitlab!26016

Add prometheus integration page in ops

See merge request gitlab-org/gitlab!24727

Resolve Migrate '.fa-spinner' to '.spinner' for 'app/views/help'

See merge request gitlab-org/gitlab!25037

Sidebar not expanding at certain resolutions

Closes #28921

See merge request gitlab-org/gitlab!25313

Document Banzai  reference filters and parsers

See merge request gitlab-org/gitlab!24190

This adds a new document describing reference processing, with
particular attention to the ReferenceFilter and ReferenceParser
types.

The new document is linked in the top-level index.

Improve footnote formatting in permissions.md

See merge request gitlab-org/gitlab!25765

Quarantine flaky test

See merge request gitlab-org/gitlab!26042

https://gitlab.com/gitlab-org/gitlab/issues/207376

Add secure coding guidelines to definition of done

See merge request gitlab-org/gitlab!25672

Seach issues in graphQl by milestone and assignees

See merge request gitlab-org/gitlab!25794

- none and any for assigne_id are supported

Remove unused CSS .ide-merge-requests-dropdown

See merge request gitlab-org/gitlab!25965

Update Group Import/Export docs

See merge request gitlab-org/gitlab!25604

documentation -  small typo in 'Secure coding guidlines'

See merge request gitlab-org/gitlab!25897

Make Repository track shard

See merge request gitlab-org/gitlab!25911

Update `convertToCamelCase` utility function to ignore leading and trailing underscores

Closes #207853

See merge request gitlab-org/gitlab!26011

Updates the convertToCamelCase function to ignore leading and trailing
underscores.

Also updates code that was relying on the old behavior.

Add confidential attribute to notes

See merge request gitlab-org/gitlab!25784