Autodetect Current Revision of Alpine Version
Created by: tomalok
- continue to use provided 'release' value if specified
- continue to use 'edge' for edge versions
- deduce 'release' value from the version on the alpine-base APK in https://dl-cdn.alpinelinux.org/alpine/v<version>/main/<arch>/
- update test profile with 3.13
Resolves #112 (closed)