chore(CI): Adjust testing matrix for Nextcloud 30 on stable30

Signed-off-by: Joas Schilling <coding@schilljs.com>

Author: nickvergessen

composer.json

@@ -22,7 +22,7 @@
 		"phpunit/phpunit": "^9.5",
 		"nextcloud/coding-standard": "^1.1.1",
 		"vimeo/psalm": "^5.16.0",
-		"nextcloud/ocp": "dev-master"
+		"nextcloud/ocp": "dev-stable30"
 	},
 	"autoload-dev": {
 		"psr-4": {