Upgrade to Ghost 5.51.0

Michi Kofler-Häusler - 13 Jun 2023

On both domains I upgraded Ghost successfully by means of Watchtower Docker container update.
v5.49.3
v5.50.0
v5.50.1
v5.50.2
v5.50.3
v5.50.4
v5.51.0