feat(plugins): add support for loading ESM plugins (#2688)

Co-authored-by: Matt Travi <programmer@travi.org>
Co-authored-by: Gregor Martynus <39992+gr2m@users.noreply.github.com>

lib/plugins/utils.js

@@ -52,14 +52,18 @@ export async function loadPlugin({cwd}, name, pluginsPath) {
     ? dirname(resolveFrom.silent(__dirname, pluginsPath[name]) || resolveFrom(cwd, pluginsPath[name]))
     : __dirname;
 
-  if (!isFunction(name)) {
-    const file = resolveFrom.silent(basePath, name) || resolveFrom(cwd, name);
-    // See https://github.com/mysticatea/eslint-plugin-node/issues/250
-    // eslint-disable-next-line node/no-unsupported-features/es-syntax
-    name = (await import(`file://${file}`)).default;
+  if (isFunction(name)) {
+    return name;
   }
 
-  return name;
+  const file = resolveFrom.silent(basePath, name) || resolveFrom(cwd, name);
+  const { default: cjsExport, ...esmNamedExports } = await import(`file://${file}`);
+
+  if (cjsExport) {
+    return cjsExport;
+  }
+
+  return esmNamedExports;
 }
 
 export function parseConfig(plugin) {