Update CHANGELOG.md for 2.4.0 release
Update CHANGELOG.md for 2.4.0 release

ryanone/hopscotch,zimmi88/hopscotch,kate2753/hopscotch,renatolotfi/hopscotch,Xephi/hopscotch,sganz/hopscotch,slietz/hopscotch,dataquestio/hopscotch,Xephi/hopscotch,stephenh/hopscotch,renatolotfi/hopscotch,linkedin/hopscotch,thbar/hopscotch,slietz/hopscotch,adcade/hopscotch,kate2753/hopscotch,Axosoft/runningjumpscotch,dataquestio/hopscotch,adcade/hopscotch,sganz/hopscotch,thbar/hopscotch,zimmi88/hopscotch,Axosoft/runningjumpscotch,stephenh/hopscotch