URL like git@github.com:siimon/prom-client.git are valid download locations. Github provides the link this way. But the tool is marking this as invalid.
package download_location must be a valid download location according to the specification, but is: git@github.com:siimon/prom-client.git

Could the specification be incorrect in this case and the tool should be able to adjust it?