Update jsoncpp to 1.8.4 (#20182)

* Update jsoncpp to 1.8.4

This fix updates the jsoncpp to 1.8.4 to address the issue
raised in 20170. The jsoncpp used in tf was old and may contain
security issues.

This fix fixes 20170.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Add JSON_HAS_INT64 define to jsoncpp build

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Fix data type conversion issue for jsoncpp.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Fix build by include "version.h"

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>