Include all vendor files in the repo to be easier for people

vendor/erusev/parsedown/test/data/fenced_code_block.md

@@ -0,0 +1,14 @@
+```
+<?php
+
+$message = 'fenced code block';
+echo $message;
+```
+
+~~~
+tilde
+~~~
+
+```php
+echo 'language identifier';
+```