all: update gopkg.in/yaml.v2 7ad95dd0798a => v2.2.2 (#1685)

Update `gopkg.in/yaml.v2` for transition to Modules (#1634).

From: `gopkg.in/yaml.v2@7ad95dd0798a`
To: `gopkg.in/[email protected]`

Diff: go-yaml/yaml@7ad95dd...v2.2.2 (96 commits)

### Goal and scope

To make the transition to Modules possible. Some dependencies at their current version have incompatible relationships with other dependencies we have. Dep was more tolerant to incompatible versions than Modules. Making this change ahead of the PR that switches us to Modules makes that PR a functional no-op.

The reason Modules is updating `yaml.v2` is because the monorepo is also dependent on `github.com/onsi/gomega` which had to be upgraded due to another dependency requirement. The version of `gomega` we're using is explicitly dependent on at least `v2.2.1` of `yaml.v2` requiring us to update to a newer version.

I'm taking the dependency all the way to `v2.2.2` which is the latest patch release. While I don't understand all the changes deeply in the diff, the changes don't appear to be significant.

As a bonus these newer versions of `yaml.v2` are released under a more desirable license, Apache License 2.0. The commit we were dependent on previously was released under LGPL 3.

Author: leighmcculloch

Gopkg.lock

@@ -92,3 +92,7 @@
 [[constraint]]
   name = "github.com/rcrowley/go-metrics"
   revision = "51425a2415d21afadfd55cd93432c0bc69e9598d"
+
+[[override]]
+  name = "gopkg.in/yaml.v2"
+  version = "=v2.2.2"