add df output

.github/workflows/tests.yml

@@ -32,10 +32,12 @@ jobs:
     steps:
       - name: Remove irrelevant software  # to free up required disk space
         run: |
+          df -h
           sudo rm -rf /opt/ghc
           sudo rm -rf /opt/hostedtoolcache/CodeQL
           sudo rm -rf /usr/local/lib/android
           sudo rm -rf /usr/share/dotnet
+          df -h
       - name: Checkout
         uses: actions/checkout@v4
       - name: Setup python