Update eslint in / from 4.11.0 to 4.15.0

[dependencies]

Dependencies.io has updated eslint (a npm dependency in /) from "4.11.0" to "4.15.0".

4.15.0

• 6ab04b5 New: Add context.report({ messageId }) (fixes #6740) (#9165) (Jed Fox)
• fc7f404 Docs: add url to each of the rules (refs #6582) (#9788) (Patrick McElhaney)
• fc44da9 Docs: fix sort-imports rule block language (#9805) (ferhat elmas)
• 65f0176 New: CLIEngine#getRules() (refs #6582) (#9782) (Patrick McElhaney)
• c64195f Update: More detailed assert message for rule-tester (#9769) (Weijia Wang)
• 9fcfabf Fix: no-extra-parens false positive (fixes: #9755) (#9795) (Erin)
• 61e5fa0 Docs: Add table of contents to Node.js API docs (#9785) (Patrick McElhaney)
• 4c87f42 Fix: incorrect error messages of no-unused-vars (fixes #9774) (#9791) (akouryy)
• bbabf34 Update: add ignoreComments option to indent rule (fixes #9018) (#9752) (Kevin Partington)
• db431cb Docs: HTTP -> HTTPS (fixes #9768) (#9768) (Ronald Eddy Jr)
• cbf0fb9 Docs: describe how to feature-detect scopeManager/visitorKeys support (#9764) (Teddy Katz)
• f7dcb70 Docs: Add note about "patch release pending" label to maintainer guide (#9763) (Teddy Katz)