install matplotlib

Author: ufechner7

.github/workflows/CI.yml

@@ -34,6 +34,9 @@ jobs:
             arch: x64
             version: 1
     steps:
+      - name: Install matplotlib
+        run: if [ "$RUNNER_OS" = "Linux" ]; then sudo apt-get install -y python3-matplotlib; fi
+        shell: bash
       - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v2
         with: