Use migration experience to inform image-meta-tag migration

[trexfeathers]

We are hoping to work with @melissaebrooks to migrate SciTools-incubator/image-meta-tag into the MetOffice organisation. As of right now we don't know what this will entail, but after #332 we will be much better informed.

So this is a placeholder to get in touch with Melissa once we have finished the migration, probably via the typical within-Met-Office support channels.