chore(deps): update ghcr.io/misp/misp-docker/misp-core docker tag to v2.5.20

This MR contains the following updates:

Package	Type	Update	Change
ghcr.io/misp/misp-docker/misp-core	ironbank-docker	patch	v2.5.18 -> v2.5.20
ghcr.io/misp/misp-docker/misp-core	stage	patch	v2.5.18 -> v2.5.20

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