Bump Ginkgo to v2

[blackpiglet]

Describe the problem/challenge you have

Bump Ginkgo to v2, and resolve potential conflicts. https://onsi.github.io/ginkgo/MIGRATING_TO_V2#major-changes

Describe the solution you'd like

Anything else you would like to add:

Environment:

• Velero version (use velero version):
• Kubernetes version (use kubectl version):
• Kubernetes installer & version:
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):

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