Signed-off-by: Jess Frazelle <me@jessfraz.com>
This enables us to remove the following patterns that required a `rm -rf /var/cache/apk`: - `apk update` - `apk add --update` - `apk add --update-cache` Supported since alpine 3.3.
Signed-off-by: Jess Frazelle <jess@mesosphere.com>