Build: Update markdownlint dependency to 0.2.0 (fixes #6781)

[DavidAnson]

No description provided.

[mention-bot]

@DavidAnson, thanks for your PR! By analyzing the annotation information on this pull request, we identified @nzakas, @alberto and @mysticatea to be potential reviewers

[eslintbot]

LGTM

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[gyandeeps]

@DavidAnson Can you update your commit message with Upgrade: . Thanks

[eslintbot]

LGTM

[DavidAnson]

@gyandeeps Done.