pixi: Don't use activate-environment

Author: jorisv

.github/workflows/macos-linux-windows-conda.yml

@@ -80,7 +80,7 @@ jobs:
         EIGENPY_BUILD_TYPE: ${{ matrix.build_type }}
         EIGENPY_CXX_FLAGS: ${{ matrix.cxx_options }}
       run: |
-        pixi run test
+        pixi run -e ${{ matrix.environment }} test
 
     - name: Build EigenPy [Windows]
       if: contains(matrix.os, 'windows')
@@ -89,7 +89,7 @@ jobs:
         CC: ${{ matrix.compiler }}
         CXX: ${{ matrix.compiler }}
       run: |
-        pixi run test
+        pixi run -e ${{ matrix.environment }} test
 
   check:
     if: always()