IOT-1583: Updating cJSON version to remove /W4 warnings.

IOT-1583: Updating cJSON version to remove /W4 warnings.

The code is updated to commit b0db7a6308f8948dd4a68f06b787cb425ce7254d
from the main cJSON repo: https://github.com/DaveGamble/cJSON.

Change-Id: I43b2bae1fa4fde5eee12f7d74990d5263f4ec51b
Signed-off-by: Pawel Winogrodzki <pawelwi@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/18381
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>
Reviewed-by: Dave Thaler <dthaler@microsoft.com>