Install micromamba for the cppinterop/xeus-cpp job

Author: anutosh491

.github/workflows/emscripten.yml

@@ -511,6 +511,13 @@ jobs:
           llvm-project
           ${{ matrix.cling=='On' && 'cling' || '' }}
         key: ${{ env.CLING_HASH }}-${{ runner.os }}-${{ matrix.os }}-${{ matrix.compiler }}-clang-${{ matrix.clang-runtime }}.x-emscripten
+
+    - name: install mamba
+      uses: mamba-org/setup-micromamba@main
+      with:
+        environment-file: environment-wasm-build.yml
+        init-shell: bash
+        environment-name: CppInterOp-wasm-build
 
     - name: Emscripten build of CppInterOp on Unix systems
       if: ${{ runner.os != 'windows' }}