[Rspamd] Add iso/img to bad extensions (#3753)

data/conf/rspamd/local.d/mime_types.conf

@@ -20,6 +20,8 @@ bad_extensions = {
   shs = 4,
   wsc = 4,
   wsf = 4,
+  iso = 8,
+  img = 8
 };
 
 # Extensions that are particularly penalized for archives
@@ -41,5 +43,5 @@ archive_extensions = {
   rar = 1,
   ace = 1,
   7z = 1,
-  cab = 1,
+  cab = 1
 };