Use is_same from Boost.TypeTraits

boost::core::is_same is deprecated, so use the one from Boost.TypeTraits.

.github/workflows/ci.yml

@@ -116,6 +116,7 @@ jobs:
           git submodule init libs/config
           git submodule init libs/core
           git submodule init libs/headers
+          git submodule init libs/type_traits
           git submodule init tools/build
           git submodule init tools/boost_install
           git submodule update
@@ -170,6 +171,7 @@ jobs:
           git submodule init libs/config
           git submodule init libs/core
           git submodule init libs/static_assert
+          git submodule init libs/type_traits
           git submodule init libs/headers
           git submodule init tools/build
           git submodule init tools/boost_install