libvips for Heroku builder

Questions / Help
1

Hello everyone,

I’m struggling to install some buildpacks that Rails requires for image-processing. Specifically what I’m trying to do is described here: ruby on rails - Could not open library 'vips.42'; Could not open library 'libvips.42.dylib' - Stack Overflow

I’ve configured fly.toml like this:

[build]
  builder = "heroku/buildpacks:20"
  buildpacks = ["https://github.com/heroku/heroku-buildpack-apt", "https://github.com/brandoncc/heroku-buildpack-vips", "heroku/nodejs", "heroku/ruby"]

The problem is I receive this from the builder:

Error failed to fetch an image or build from source: downloading buildpack: extracting from https://github.com/heroku/heroku-buildpack-apt: inspecting buildpack blob: failed to get next tar entry: archive/tar: invalid tar header

I guess what I’m confused about is whether I’m using Heroku buildpacks or whether they’re CNB-specific Heroku buildpacks (or are they the same thing?) and how to properly reference them so that the builder can use them.