bump version to 2.15
bump version to 2.15

saydulk/newfies-dialer,newfies-dialer/newfies-dialer,romonzaman/newfies-dialer,Star2Billing/newfies-dialer,Star2Billing/newfies-dialer,saydulk/newfies-dialer,romonzaman/newfies-dialer,newfies-dialer/newfies-dialer,romonzaman/newfies-dialer,saydulk/newfies-dialer,newfies-dialer/newfies-dialer,saydulk/newfies-dialer,romonzaman/newfies-dialer,newfies-dialer/newfies-dialer,Star2Billing/newfies-dialer,Star2Billing/newfies-dialer