vendor: Rollback gopkg.in/yaml.v2 to v2.2.8

[bobbypage]

Switch back to gopkg.in/[email protected]

go get gopkg.in/[email protected]

gopkg.in/[email protected] has a breaking change that is affecting being able to vendor cadvisor into k/k ref kubernetes/kubernetes#96425 (comment) and go-yaml/yaml#670

gopkg.in/[email protected] is a transitive dependency of github.com/prometheus/[email protected]. cadvisor moved to github.com/prometheus/[email protected] as part of #2716

Downgrade dependent modules (e.g. github.com/prometheus/common) for now to ensure we can stay on gopkg.in/[email protected].

[bobbypage]

/cc @dims @dashpole

[dashpole]

can you link to where it was bumped in the first place?

[bobbypage]

It's a transitive dependency of github.com/prometheus/common.

#2716 bumped github.com/prometheus/[email protected] to github.com/prometheus/[email protected] in cadvisor.

In turn the bump of gopkg.in/[email protected] in github.com/prometheus/common happened in prometheus/common#242