remove ":edge" from "Try in a Docker Container"

[gubsey]

The Try in a Docker Container section of the install page points to the "edge" tag for the "alpine" image. This variant is not intended for use in production as there are constant breaking changes. I myself was having the script break when trying to connect to "github.com". A simple fix is to change "edge" to "latest".

[siduck]

fixed in recent commits