Update changelog for 0.2.4 release
Update changelog for 0.2.4 release

dreadjr/firebase-util,googlearchive/firebase-util,bookbottles/firebase-util,sbolel/firebase-util,bookbottles/firebase-util,maxrevilo/firebase-util,dreadjr/firebase-util,maksymilian-majer/firebase-util,maxrevilo/firebase-util,sbolel/firebase-util,maksymilian-majer/firebase-util,googlearchive/firebase-util