Rename .h header files to .hpp

Majority of the project uses .hpp and .h shouldn't be used for C++
header files anyway.

Change-Id: I979ba2d243f8f5dbf45c37237ac4aaf9a733eba8
diff --git a/src/python_netconf.cpp b/src/python_netconf.cpp
index 260395a..49a4339 100644
--- a/src/python_netconf.cpp
+++ b/src/python_netconf.cpp
@@ -9,7 +9,7 @@
 #include <pybind11/pybind11.h>
 #include <pybind11/stl.h>
 #include "netconf_access.hpp"
-#include "netconf-client.h"
+#include "netconf-client.hpp"
 
 using namespace std::literals;
 using namespace pybind11::literals;