Another test workflow tweak

Author: jonathanhogg

.github/workflows/ci-test.yml

@@ -41,7 +41,7 @@ jobs:
       if: matrix.os == 'ubuntu-latest' || matrix.os == 'ubuntu-24.04-arm'
       run: |
         sudo apt-get update
-        sudo apt-get install libasound2-dev libjack-jackd2-dev
+        sudo apt-get install libasound2-dev libjack-jackd2-dev libx11-dev
     - name: Build and install package
       run: |
         python -m pip install .