* Update version and release note to 1.9.3

This PR update version and release note to prepare for 1.9.3.
Main reason is to address CVE-2022-27191 and CVE-2022-28948
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Update notes/coredns-1.9.3.md
Co-authored-by: Chris O'Haver <cohaver@infoblox.com>
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Update notes/coredns-1.9.3.md
Co-authored-by: Chris O'Haver <cohaver@infoblox.com>
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Co-authored-by: Chris O'Haver <cohaver@infoblox.com>