chore(deps): bump gopkg.in/yaml.v2 from 2.2.2 to 2.2.8

Bumps gopkg.in/yaml.v2 from 2.2.2 to 2.2.8.

---
updated-dependencies:
- dependency-name: gopkg.in/yaml.v2
  dependency-version: 2.2.8
  dependency-type: direct:production
...

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