added release date in changelog for 1.2 version
added release date in changelog for 1.2 version

tautrimas/ElasticsearchBundle,saimaz/ElasticsearchBundle,murnieza/ElasticsearchBundle,martiis/ElasticsearchBundle,asev/ElasticsearchBundle,saimaz/ElasticsearchBundle,ongr-io/ElasticsearchBundle,trandangtri/ElasticsearchBundle,asev/ElasticsearchBundle,tautrimas/ElasticsearchBundle,martiis/ElasticsearchBundle,murnieza/ElasticsearchBundle,trandangtri/ElasticsearchBundle