Install headless opencv only for linux

Author: dnerini

.github/workflows/test_pysteps.yml

@@ -33,7 +33,19 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
 
-      - name: Install mamba and create environment
+      - name: Install mamba and create environment for Linux
+        if: matrix.os == 'ubuntu-latest'
+        uses: mamba-org/setup-micromamba@v1
+        with:
+          environment-file: ci/ci_test_env.yml
+          environment-name: test_environment
+          generate-run-shell: false
+          create-args: >-
+            python=${{ matrix.python-version }}
+            libopencv *=headless*
+
+      - name: Install mamba and create environment (not Linux)
+        if: matrix.os != 'ubuntu-latest'
         uses: mamba-org/setup-micromamba@v1
         with:
           environment-file: ci/ci_test_env.yml

ci/ci_test_env.yml

@@ -15,7 +15,6 @@ dependencies:
   - matplotlib
   - netCDF4
   - opencv
-  - libopencv *=headless*
   - pillow
   - pyproj
   - scipy