Fix some code quality issues.

Author: rvdsteege

composer.json

@@ -23,9 +23,12 @@
 		"bamarni/composer-bin-plugin": "^1.4",
 		"php-coveralls/php-coveralls": "^2.4",
 		"phpmd/phpmd": "^2.9",
+		"phpstan/phpstan": "^1.11",
 		"pronamic/pronamic-cli": "^1.1",
 		"pronamic/wp-coding-standards": "^2.2",
 		"roots/wordpress": "^6.0",
+		"szepeviktor/phpstan-wordpress": "^1.3",
+		"vimeo/psalm": "^5.25",
 		"yoast/phpunit-polyfills": "^1.0"
 	},
 	"scripts": {

phpstan.neon.dist

@@ -1,5 +1,5 @@
 includes:
-	- vendor-bin/phpstan/vendor/szepeviktor/phpstan-wordpress/extension.neon
+	- vendor/szepeviktor/phpstan-wordpress/extension.neon
 parameters:
 	customRulesetUsed: false
 	level: max

src/Response.php

@@ -108,7 +108,7 @@ public function json() {
 					\esc_html( (string) \strlen( $body ) ),
 					\esc_html( \json_last_error_msg() )
 				),
-				\esc_html( $json_error )
+				(int) $json_error
 			);
 		}