update docker build to 1.0.0-RC3
update docker build to 1.0.0-RC3

cgreenhalgh/opensharingtoolkit-mediahub,cgreenhalgh/opensharingtoolkit-mediahub,cgreenhalgh/opensharingtoolkit-mediahub,cgreenhalgh/opensharingtoolkit-mediahub,cgreenhalgh/opensharingtoolkit-mediahub