Update doctrine/coding-standard requirement from ^12.0 to ^13.0 (#10)

Author: dependabot[bot]

composer.json

@@ -19,7 +19,7 @@
 	"require": {
 		"php": ">=7.4",
 		"dealerdirect/phpcodesniffer-composer-installer": "^1.0",
-		"doctrine/coding-standard": "^12.0",
+		"doctrine/coding-standard": "^13.0",
 		"wp-coding-standards/wpcs": "^3.1"
 	},
 	"config": {