Maybe no need for the custom action?

.github/workflows/gh_actions_ci.yml

@@ -121,11 +121,10 @@ jobs:
           python-version: "3.10"
           channels: conda-forge
           channel-priority: strict
-      - uses: ilammy/msvc-dev-cmd@v1
       - name: Build
         shell: pwsh
         run: |
-          conda install -y python=3.10 git pybind11 numpy cmake 'llvmdev=18.*' tbb-devel tbb astroquery libboost-devel fmt spdlog sleef sympy cloudpickle zlib libzlib 'mppp=1.*' numba
+          conda install -y python=3.10 git pybind11 numpy cmake llvmdev tbb-devel tbb astroquery libboost-devel fmt spdlog sleef sympy cloudpickle zlib libzlib 'mppp=1.*' numba
           git clone --depth 1 https://github.com/bluescarni/heyoka.git heyoka_cpp
           cd heyoka_cpp
           mkdir build