style: Fix editorconfig indent for config/*config.php

*config.php is created with var_export, which indents lines with two
spaces.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

.editorconfig

@@ -31,3 +31,7 @@ indent_style = space
 [build/psalm-baseline.xml]
 indent_size = 2
 indent_style = space
+
+[config/*config.php]
+indent_size = 2
+indent_style = space