Port to libyang-cpp and sysrepo-cpp API change to std::string

Change-Id: I9e683e0ab3a5db696c35699d22cf1cb982c8ceda
Depends-on: https://gerrit.cesnet.cz/c/CzechLight/dependencies/+/5564
diff --git a/src/libyang_utils.cpp b/src/libyang_utils.cpp
index f3881fe..b09454e 100644
--- a/src/libyang_utils.cpp
+++ b/src/libyang_utils.cpp
@@ -123,9 +123,9 @@
 
 libyang::DataNode treeToRpcInput(libyang::Context ctx, const std::string& path, DatastoreAccess::Tree in)
 {
-    auto root = ctx.newPath(path.c_str(), nullptr, libyang::CreationOptions::Update);
+    auto root = ctx.newPath(path, std::nullopt, libyang::CreationOptions::Update);
     for (const auto& [k, v] : in) {
-        root.newPath(k.c_str(), leafDataToString(v).c_str(), libyang::CreationOptions::Update);
+        root.newPath(k, leafDataToString(v), libyang::CreationOptions::Update);
     }
 
     return root;