Release 15.9.52

• Upgrade eslint-plugin-ava 6.0.0 -> 7.0.0 (c215283)
• Use new rules for eslint-plugin-ava (ed0bd10)
• Upgrade gulp-shared-tasks 0.28.9 -> 0.29.0 (aeb3df7)
• Upgrade gulp-shared-tasks 0.28.8 -> 0.28.9 (92a910c)
• Upgrade gulp-shared-tasks 0.28.7 -> 0.28.8 (18a60a7)