Move away from development channel for emscripten forge packages

Author: mcbarton

environment-wasm-build.yml

@@ -1,6 +1,6 @@
 name: xeus-cpp-wasm-build
 channels:
-  - https://repo.prefix.dev/emscripten-forge-dev
+  - https://repo.mamba.pm/emscripten-forge
   - conda-forge
 dependencies:
   - cmake

environment-wasm-host.yml

@@ -1,6 +1,6 @@
 name: xeus-cpp-wasm-host
 channels:
-  - https://repo.prefix.dev/emscripten-forge-dev
+  - https://repo.mamba.pm/emscripten-forge
   - https://repo.mamba.pm/conda-forge
 dependencies:
   - nlohmann_json