xercesc 3.2.2 namespace update

[armtir]

Hi,

this error occures, when building this library.

/workspaces/vscode-remote-try-cpp-master/lib/OpenADR-VEN-Library-0.7.0/OpenADR-VEN-Library-0.7.0/oadr/oadr/manager/../manager/../ven/VEN2b.h:355:17: error: ‘xercesc_3_1’ is not a namespace-name
using namespace xercesc_3_1;
^~~~~~~~~~~
/workspaces/vscode-remote-try-cpp-master/lib/OpenADR-VEN-Library-0.7.0/OpenADR-VEN-Library-0.7.0/oadr/oadr/manager/../manager/../ven/VEN2b.h:355:28: error: expected namespace-name before ‘;’ token
using namespace xercesc_3_1;

using namespace XERCES_CPP_NAMESPACE;

has solved the problem for me. #2