Drop pin on nlohmann_json in environment-wasm-host.yml

Author: mcbarton

environment-wasm-host.yml

@@ -3,7 +3,7 @@ channels:
   - https://repo.prefix.dev/emscripten-forge-dev
   - https://repo.mamba.pm/conda-forge
 dependencies:
-  - nlohmann_json=3.12.0
+  - nlohmann_json
   - xeus-lite
   - xeus
   - CppInterOp