Update high_trust_sender_root_domains.txt (#590)

Co-authored-by: Sorted Order Validation <hello@sublimesecurity.com>

Author: brycampbell

high_trust_sender_root_domains.txt

@@ -122,6 +122,7 @@ datadoghq.com
 dataminr.com
 datasite.com
 dell.com
+deloitte.co.uk
 deloitte.com
 delta.com
 depconfirm.com