Image V2: Properties reference is hidden Images JSON serialization

[michal-gubricky]

The Properties reference is hidden for the Images JSON serialization:

gophercloud/openstack/image/v2/images/requests.go

Line 190 in df37077

Properties map[string]string `json:"-"`

it could be useful to not map the Properties field to json:"-" in a struct because I didn't find another way to unmarshal the properties reference when creating an image.

[github-actions]

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