This method used to use a UNION, which would lead to it performing the
same query twice; producing less than ideal performance. Further, in
certain cases ActiveRecord could get confused and mess up the variable
bindings, though it's not clear how/why exactly this happens.

Fortunately we can work around all of this by building some of the WHERE
conditions manually, allowing us to use a simple OR statement to get all
the data we want without any of the above problems.

This changes ProjectsFinder#init_collection so it no longer relies on a
UNION. For example, to get starred projects of a user we used to run:

    SELECT projects.*
    FROM projects
    WHERE projects.pending_delete = 'f'
    AND (
        projects.id IN (
            SELECT projects.id
            FROM projects
            INNER JOIN users_star_projects
                ON users_star_projects.project_id = projects.id
            INNER JOIN project_authorizations
                ON projects.id = project_authorizations.project_id
            WHERE projects.pending_delete = 'f'
            AND project_authorizations.user_id = 1
            AND users_star_projects.user_id = 1

            UNION

            SELECT projects.id
            FROM projects
            INNER JOIN users_star_projects
                ON users_star_projects.project_id = projects.id
            WHERE projects.visibility_level IN (20, 10)
            AND users_star_projects.user_id = 1
        )
    )
    ORDER BY projects.id DESC;

With these changes the above query is turned into the following instead:

    SELECT projects.*
    FROM projects
    INNER JOIN users_star_projects
        ON users_star_projects.project_id = projects.id
    WHERE projects.pending_delete = 'f'
    AND (
        EXISTS (
            SELECT 1
            FROM project_authorizations
            WHERE project_authorizations.user_id = 1
            AND (project_id = projects.id)
        )
        OR projects.visibility_level IN (20,10)
    )
    AND users_star_projects.user_id = 1
    ORDER BY projects.id DESC;

This query in turn produces a better execution plan and takes less time,
though the difference is only a few milliseconds (this however depends
on the amount of data involved and additional conditions that may be
added).

Speed up counting approvers when some are specified

See merge request !2196

Change GitLab version for object storage

See merge request !2197

Document the manual steps needed to use repmgr

See merge request !2172

[ci skip]

[ci skip]

[ci skip]

When some approvers are specified, we still need to check the potential set of
approvers, including people with developer access and up. Doing that with an OR
took a long time (over 500ms) on GitLab.com, even when only one approver was
specified.

By doing a UNION instead, we get much faster results (less than 10ms). Also, as
we are using UNION and not UNION ALL, we don't need to exclude the approvers
specified from the query to get everyone with access.

Fix bad connector - verify if both new and resolved issues are present before adding the connector.

Closes #2676

See merge request !2187

Re-enable autocomplete for milestones, tags, releases, and wiki --  EE merge edition

Closes gitlab-ce#33598

See merge request !2170

Resolve "Cross-project pipelines are broken"

Closes #2682

See merge request !2166

Fix avatar images in pipeline and approval emails

See merge request !2182

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/33598

Fix some failing specs on master

Closes #2694

See merge request !2180

Add docs for multi-project pipelines graphs

See merge request !2136

Add link to issue for MySQL/subgroups drop support

See merge request !2184

Fix quoted example in triggers docs

Closes #2686

See merge request !2171

Mention limitations of MySQL in docs

See merge request !2165

Add info about artifacts object storage in docs

Closes #2311

See merge request !2147

Change a few missing `login_as` to `gitlab_sign_in`

See merge request !2176

[EE] Prepare for bypassing GitLab sign in in feature specs

See merge request !2140

Enable autocomplete on project snippets -- EE merge edition

See merge request !2174

CE upstream: Thursday

Closes gitlab-ce#31782, gitlab-ce#33529, gitlab-ce#32861, gitlab-ce#33483, #2525, gitlab-ce#31263, gitlab-ce#33403, and gitlab-ce#33106

See merge request !2137

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/1210 disabled
autocomplete for personal snippets and project snippets. But we want
autocomplete on project snippets.

Disable autocomplete on snippets comments -- EE merge edition

Closes gitlab-ce#33594

See merge request !2167