LEAccount Warning if LetsEncrypt omits contact

[skwirrel]

We have experienced occassional warnings generated in LEAccount.php around line 136:

            $this->id = isset($post['body']['id']) ? $post['body']['id'] : '';
            $this->key = $post['body']['key'];
>>>     $this->contact = $post['body']['contact'];   <<< HERE

I'm not entirely sure why but it seems that LetsEncrypt sometimes fails to return a contact. Using a null coalescing operator to supply a default empty array fixed this for us thus:
$this->contact = $post['body']['contact'] ?? [];

Hope that helps.