fix(config-conventional): use default export

Author: dargmuesli

@commitlint/config-conventional/src/index.test.ts

@@ -1,5 +1,5 @@
 import lint from '@commitlint/lint';
-import {config} from '.';
+import config from '.';
 
 const commitLint = async (message) => {
 	const preset = await require(config.parserPreset)();

@commitlint/config-conventional/src/index.ts

@@ -4,7 +4,7 @@ import {
 	TargetCaseType,
 } from '@commitlint/types';
 
-export const config = {
+export = {
 	parserPreset: 'conventional-changelog-conventionalcommits',
 	rules: {
 		'body-leading-blank': [RuleConfigSeverity.Warning, 'always'] as const,