Use step key for github status names

Right now when using the “create a status for each step” option, the status names are based on the step labels, which mean mine all are awkwardly named since the first piece of each label is an emoji and that ends up in the status name. One option would be to make it smart enough to skip emoji in there, but a more direct solution would be to use the step key if set since that’s already a short unique ID.