BREAKING: allow hashes provided as a URL to a text file or a string

(closes #1)

lib/download.js

@@ -0,0 +1,20 @@
+import stream from "stream";
+import { promisify } from "util";
+import fs from "fs-extra";
+import got from "got";
+
+import debug from "./debug.js";
+
+// Download any file to any destination. Returns a promise.
+export default async (url, dest) => {
+  debug(`Downloading '${url}' to '${dest}'`);
+
+  // get remote file and write locally
+  const pipeline = promisify(stream.pipeline);
+  const download = pipeline(
+    got.stream(url, { followRedirect: true }), // GitHub releases redirect to unpredictable URLs
+    fs.createWriteStream(dest),
+  );
+
+  return download;
+};