Adding INT64 Tensor support.

include/aidge/backend/cpu/data/TensorImpl.hpp

@@ -177,6 +177,8 @@ static Registrar<Tensor> registrarTensorImpl_cpu_Float16(
         {"cpu", DataType::Float16}, Aidge::TensorImpl_cpu<half_float::half>::create);
 static Registrar<Tensor> registrarTensorImpl_cpu_Int32(
         {"cpu", DataType::Int32}, Aidge::TensorImpl_cpu<int>::create);
+static Registrar<Tensor> registrarTensorImpl_cpu_Int64(
+        {"cpu", DataType::Int64}, Aidge::TensorImpl_cpu<long>::create);
 }  // namespace
 }  // namespace Aidge