Update CHANGELOG.md
Update CHANGELOG.md

with details of 15.03.1 Release
Vishwa1311/incubator-fineract,RanjithKumar5550/RanMifos,Vishwa1311/incubator-fineract,RanjithKumar5550/RanMifos,Vishwa1311/incubator-fineract,RanjithKumar5550/RanMifos