fix(deps): update dependency addons-linter to v2.7.0

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
addons-linter	dependencies	minor	2.5.0 -> 2.7.0

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Release Notes

mozilla/addons-linter

v2.7.0

Compare Source

• Added: DOMPurify 2.10.0 has been added to the list of denied libraries (#​3356)
• Updated: minor dependency updates

v2.6.0

Compare Source

• Added: added DOMPurify 2.0.17 to forbidden list, due to a security vulnerability, see https://github.com/cure53/DOMPurify/releases/tag/2.1.0
• Fixed: increased jest timeout when running test.linter.js on nodejs 10 (#​3351)
• Updated: minor dependency updates

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[coveralls]

Coverage remained the same at 100.0% when pulling 8b453fc on renovate/addons-linter-2.x into c5185bf on master.