fix: resolves plugins from extended configs

Author: Julius Celik

@commitlint/load/src/load.ts

@@ -3,6 +3,7 @@ import Path from 'path';
 import merge from 'lodash/merge';
 import mergeWith from 'lodash/mergeWith';
 import pick from 'lodash/pick';
+import union from 'lodash/union';
 import resolveFrom from 'resolve-from';
 
 import executeRule from '@commitlint/execute-rule';
@@ -84,6 +85,10 @@ export default async function load(
 			resolveFrom.silent(base, config.formatter) || config.formatter;
 	}
 
+	// Read plugins from extends
+	if (Array.isArray(extended.plugins))
+		config.plugins = union(config.plugins, extended.plugins || []);
+
 	// resolve plugins
 	if (Array.isArray(config.plugins)) {
 		config.plugins.forEach(plugin => {