Docs update release checklist and generator

See merge request gitlab-org/gitlab-runner!1073

Add  failure reason for execution timeout

See merge request gitlab-org/gitlab-runner!1051

Fixing Substrakt Health URL

See merge request gitlab-org/gitlab-runner!1064

Don't use cache when building official Docker images

See merge request gitlab-org/gitlab-runner!1067

Update runner release docs

See merge request gitlab-org/gitlab-runner!1070

Point to the release check list instead, to only have a single source of
truth.

Add a prepare_release_checklist_issue_dry_run make task

See merge request gitlab-org/gitlab-runner!1066

Updating Docs links from /ce to /ee

See merge request gitlab-org/gitlab-runner!1061

Don't run coverage stage jobs when only docs are being updated

See merge request gitlab-org/gitlab-runner!1065

Docs: Fixing some bad links in Runner docs.

See merge request gitlab-org/gitlab-runner!1056

Refactor and improve testing of log package

See merge request gitlab-org/gitlab-runner!1039

Add missing error checks

See merge request gitlab-org/gitlab-runner!1062

* 11-4-stable:
  Update CHANGELOG for v11.4.0
  Merge branch '3639-follow-up-from-resolve-add-docker-support-for-interactive-web-terminal' into 'master'
  Merge branch 'master' into 'master'

Files are being written to without checking the error message, which
might lead to false positives or hard to debug tests.

Generate junit report file for tests

See merge request gitlab-org/gitlab-runner!1060

Docs: changing secret variable to just variable in advanced-configuration.md

See merge request gitlab-org/gitlab-runner!1055