Pin nlohmann_json to the last working version (#53)

Author: anutosh491

README.md

@@ -32,7 +32,7 @@ source activate  "xeus-cpp"
 ```
 We will now install the dependencies needed to compile xeux-cpp from source within this environment by executing the following
 ```bash
-mamba install notebook cmake cxx-compiler xeus-zmq nlohmann_json cppzmq xtl jupyterlab clangdev=16 cpp-argparse pugixml doctest -c conda-forge
+mamba install notebook cmake cxx-compiler xeus-zmq nlohmann_json=3.11.2 cppzmq xtl jupyterlab clangdev=16 cpp-argparse pugixml doctest -c conda-forge
 ```
 Now you can compile the kernel from the source by executing (replace `$CONDA_PREFIX` with a custom installation prefix if need be)
 ```bash

environment-dev.yml

@@ -8,7 +8,7 @@ dependencies:
   - cxx-compiler
   # Host dependencies
   - xeus-zmq >=1.0.2,<2.0
-  - nlohmann_json
+  - nlohmann_json=3.11.2
   - cppzmq
   - xtl
   - clangdev >=16,<17