need process to ensure using current rev of Alpine for runtime-lite docker image

- Alpine releases are listed [here](https://alpinelinux.org/releases/)
- runtime-lite docker file is [here](https://github.com/simonsdave/cloudfeaster/blob/master/dockerfiles/runtime-lite/Dockerfile)
- docker image versions are [here](https://hub.docker.com/_/alpine?tab=tags) although not sure these are needed