Setup recommended eslint preset (#1345)

This is usually enough to prevent silly mistakes.
Formatting will be done by prettier after merging pull requests.

lib/svgo-node.js

@@ -39,6 +39,7 @@ const loadConfig = async (configFile, cwd = process.cwd()) => {
     }
   }
   let dir = cwd;
+  // eslint-disable-next-line no-constant-condition
   while (true) {
     const file = path.join(dir, "svgo.config.js");
     if (await isFile(file)) {