Upgraded nlohamnn_json version (#662)

* Upgraded nlohamnn_json version

* Removed xeus from environment file

Author: JohanMabille

environment-dev.yml

@@ -8,9 +8,8 @@ dependencies:
   - ninja
   - cmake < 4  # TODO: remove pin on CMake
   # Host dependencies
-  - xeus>=5.0.0
-  - xeus-zmq>=3.0,<4.0
-  - nlohmann_json=3.11.3
+  - xeus-zmq>=3.1,<4.0
+  - nlohmann_json=3.12.0
   - pybind11>=2.6.1,<3.0
   - pybind11_json>=0.2.6,<0.3
   - xeus-python-shell>=0.6.3,<0.7