ADD instruction does not download remote files

[raulsh]

Hi,

ADD instructio doesnt download remote files a Docker does.

Line in my Dockerfile:
ADD https://deb.nodesource.com/setup_8.x ./setup_8.x

Makisu logs
[build:4] {"level":"error","ts":1607830422.6434479,"msg":"failed to create build plan: process stages and aliases: failed to convert parsed stage: new dockerfile steps: directive to build step: set cache id: hash context sources: walk /drone/src/https:/deb.nodesource.com/setup_8.x: prev error during walk: lstat /drone/src/https:/deb.nodesource.com/setup_8.x: no such file or directory"}