Added phpstan baseline

.gitattributes

@@ -5,4 +5,5 @@
 /.gitignore export-ignore
 /phpcs.xml export-ignore
 /phpstan.neon export-ignore
+/phpstan-baseline.neon export-ignore
 /phpunit.xml export-ignore

phpstan-baseline.neon

@@ -0,0 +1,6 @@
+parameters:
+	ignoreErrors:
+		-
+			message: "#^Parameter \\#2 \\$callback of method flight\\\\core\\\\Dispatcher\\:\\:set\\(\\) expects Closure\\(\\)\\: mixed, array\\{\\$this\\(flight\\\\Engine\\), literal\\-string&non\\-falsy\\-string\\} given\\.$#"
+			count: 1
+			path: flight/Engine.php

phpstan.neon

@@ -1,5 +1,6 @@
 includes:
     - vendor/phpstan/phpstan/conf/bleedingEdge.neon
+    - phpstan-baseline.neon
 
 parameters:
     level: 6