Update goharbor/harbor-exporter Docker tag to v2.3.1

This MR contains the following updates:

Package	Type	Update	Change
goharbor/harbor-exporter	ironbank-docker	patch	v2.3.0 -> v2.3.1
goharbor/harbor-exporter		patch	v2.3.0 -> v2.3.1
goharbor/harbor-exporter	stage	patch	v2.3.0 -> v2.3.1

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