update

Author: joeyh

doc/todo/optimise_by_converting_Map_to_HashMap.mdwn

@@ -8,5 +8,5 @@ parts with HashMap. The uses in AnnexRead especially.
 
 > Note that HashMap perfomance can degrade if an attacker provides keys
 > that collide. This has been used to DOS aeson parsing. (Which could
-> affect a few parts of git-annex in theory). So if converting to HashMap,
-> need to consider this. --[[Joey]]
+> affect a few parts of git-annex in theory; fixed in aeson-2.0.1.0). 
+> So if converting to HashMap, need to consider this. --[[Joey]]