Adapt to change in Conan recipe for NuDB (XRPLF#4615)

The recipe was updated a few days ago and the exported library target was renamed.

CMakeLists.txt

@@ -113,7 +113,6 @@ target_link_libraries(ripple_libs INTERFACE
   ed25519::ed25519
   LibArchive::LibArchive
   lz4::lz4
-  nudb::core
   OpenSSL::Crypto
   OpenSSL::SSL
   Ripple::grpc_pbufs
@@ -123,6 +122,16 @@ target_link_libraries(ripple_libs INTERFACE
   SQLite::SQLite3
 )
 
+# Work around changes to Conan recipe for now.
+if(TARGET nudb::core)
+  set(nudb nudb::core)
+elseif(TARGET NuDB::nudb)
+  set(nudb NuDB::nudb)
+else()
+  message(FATAL_ERROR "unknown nudb target")
+endif()
+target_link_libraries(ripple_libs INTERFACE ${nudb})
+
 if(reporting)
   find_package(cassandra-cpp-driver REQUIRED)
   find_package(PostgreSQL REQUIRED)