Update goharbor/harbor-portal Docker tag to v2.9.0

This MR contains the following updates:

Package	Type	Update	Change
goharbor/harbor-portal	ironbank-docker	minor	v2.8.4 -> v2.9.0
goharbor/harbor-portal		minor	v2.8.4 -> v2.9.0
goharbor/harbor-portal	stage	minor	v2.8.4 -> v2.9.0

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