Update release notes for v1.2.5
Update release notes for v1.2.5

0312birdzhang/alerta,skob/alerta,guardian/alerta,guardian/alerta,0312birdzhang/alerta,0312birdzhang/alerta,guardian/alerta,skob/alerta,mrkeng/alerta,skob/alerta,mrkeng/alerta,guardian/alerta,mrkeng/alerta,skob/alerta,mrkeng/alerta