Skaffold Snap (ubuntu linux et al) -- old version in snapcraft.io

### Expected behavior
On ubuntu (and other) linux installations.

`$ snap install skaffold` -- should install the latest stable version of skaffold

### Actual behavior
Currently installs a version from March 2019, v0.25.0

### Information

https://github.com/tuapuikia/skaffold-snap -- is this the publisher? (dates line up)

https://snapcraft.io/skaffold -- the snap page.

A `snapcraft.yaml` in this repo that publishes via CI would be ideal, it would always be current.