Fix Implode signature

The following triggered an error locally...

```
return implode( $lines, "\n" );
```

By switching the operands so that glue comes first and collection second. I believe this might help this to work

Author: Lewiscowles1986

src/ScaffoldPackageCommand.php

@@ -706,7 +706,7 @@ private static function indent( $whitespace, $text ) {
 		foreach ( $lines as &$line ) {
 			$line = $whitespace . $line;
 		}
-		return implode( $lines, "\n" );
+		return implode( "\n", $lines );
 	}
 
 	private function prompt_if_files_will_be_overwritten( $filename, $force ) {