WIP: test: Ginkgo and Gomega update

[pohly]

The new Gomega version supports testing a function with no return
value (onsi/gomega#198 (comment)). This
makes it possible to simplify the metrics test.

[pohly]

We need a formal Gomega release.

[pohly]

Updating to Ginkgo 2.0 once released (see https://github.com/onsi/ginkgo/blob/v2/docs/MIGRATING_TO_V2.md) will also be useful.

Currently we get a deprecation warning:

inkgo 2.0 is under active development and will introduce (a small number of) breaking changes.
To learn more, view the migration guide at https://github.com/onsi/ginkgo/blob/v2/docs/MIGRATING_TO_V2.md
To comment, chime in at https://github.com/onsi/ginkgo/issues/711

  You are using a custom reporter.  Support for custom reporters will likely be removed in V2.  Most users were using them to generate junit or teamcity reports and this functionality will be merged into the core reporter.  In addition, Ginkgo 2.0 will support emitting a JSON-formatted report that users can then manipulate to generate custom reports.

  If this change will be impactful to you please leave a comment on https://github.com/onsi/ginkgo/issues/711
  Learn more at: https://github.com/onsi/ginkgo/blob/v2/docs/MIGRATING_TO_V2.md#removed-custom-reporters

To silence deprecations that can be silenced set the following environment variable:
  ACK_GINKGO_DEPRECATIONS=1.16.4

[pohly]

This is getting closer to becoming feasible: once Kubernetes 1.25 and kubernetes-csi/csi-test#366 are released, all of our dependencies use ginkgo v2.