Use a prebuilt image

.devcontainer/Dockerfile

@@ -1,6 +1,6 @@
-# Update the VARIANT arg in docker-compose.yml to pick an Elixir version: 1.9, 1.10, 1.10.4
+# Update the VARIANT arg to pick an Elixir version: latest, 1.11.4, etc.
 ARG VARIANT=latest
-FROM elixir:${VARIANT}
+FROM docker.pkg.github.com/processone/docker-build/elixir:${VARIANT}
 
 # This Dockerfile adds a non-root user with sudo access. Update the “remoteUser” property in
 # devcontainer.json to use it. More info: https://aka.ms/vscode-remote/containers/non-root-user.