Add OMERO-5.1-{latest,merge}-deploy-win jobs to contributing

Adds the 5.1 Windows deployment jobs to the docs
https://ci.openmicroscopy.org/job/OMERO-5.1-latest-deploy-win/
https://ci.openmicroscopy.org/job/OMERO-5.1-merge-deploy-win/
the other links in the section are all 'https', is using 'http' here intentional?