CI: Fix Python on macOS

.github/workflows/macos.yml

@@ -22,13 +22,16 @@ jobs:
       #CMAKE_GENERATOR: Ninja
     steps:
     - uses: actions/checkout@v4
-    - name: install dependencies
+    - uses: actions/setup-python@v5
+      name: Install Python
+      with:
+        python-version: '3.x'
+    - name: install brew dependencies
       run: |
         set +e
         brew unlink gcc
         brew update
         brew upgrade || true
-        brew install --overwrite python
         brew install ccache
         brew install fftw
         brew install libomp
@@ -39,12 +42,12 @@ jobs:
         set -e
         brew tap openpmd/openpmd
         brew install openpmd-api
-
-        python3 -m venv py-venv
-        source py-venv/bin/activate
+    - name: install pip dependencies
+      run: |
         python3 -m pip install --upgrade pip
         python3 -m pip install --upgrade build packaging setuptools wheel
         python3 -m pip install --upgrade mpi4py
+        python3 -m pip install --upgrade -r Regression/requirements.txt
     - name: CCache Cache
       uses: actions/cache@v4
       with:
@@ -60,8 +63,6 @@ jobs:
         export CCACHE_SLOPPINESS=time_macros
         ccache -z
 
-        source py-venv/bin/activate
-
         cmake -S . -B build_dp         \
           -DCMAKE_VERBOSE_MAKEFILE=ON  \
           -DWarpX_EB=OFF               \
@@ -71,7 +72,6 @@ jobs:
 
         cmake -S . -B build_sp         \
           -DCMAKE_VERBOSE_MAKEFILE=ON  \
-          -DPython_EXECUTABLE=$(which python3) \
           -DWarpX_EB=OFF               \
           -DWarpX_PYTHON=ON            \
           -DWarpX_OPENPMD=ON           \
@@ -85,7 +85,6 @@ jobs:
 
     - name: run pywarpx
       run: |
-        source py-venv/bin/activate
         export OMP_NUM_THREADS=1
 
         mpirun -n 2 Examples/Physics_applications/laser_acceleration/inputs_test_3d_laser_acceleration_picmi.py