Update SECURITY.md

update to match NASTY_METACHARS in src/nrpe.c

5bf9b2047f8e9a8609c3b95b2e655368765e4dd1 - adds \r\n
5aed5122c89ed917f6410197bda8ed93e069ffea - removes "

SECURITY.md

@@ -64,7 +64,7 @@ To help prevent some nasty things from being done by evil
 clients, the following metacharacters are not allowed
 in client command arguments:
 
-	| ` & > < ' " \ [ ] { } ; !
+	| ` & > < ' \ [ ] { } ; ! \r \n
 
 Any client request which contains the above mentioned metachars
 is discarded.