Don't error out if cleanup fails (model-checking#2708)

Benchcomp CI is now broken due to model-checking#2704. The clean up we are performing is a best effort at this point, but it shouldn't fail the regression if it doesn't work.

.github/actions/setup/action.yml

@@ -18,7 +18,7 @@ runs:
         run: |
           # inspired by https://github.com/easimon/maximize-build-space/blob/master/action.yml
           df -h
-          sudo rm -r /usr/share/dotnet /usr/local/lib/android /usr/local/.ghcup
+          sudo rm -rf /usr/share/dotnet /usr/local/lib/android /usr/local/.ghcup
           df -h
 
       - name: Install dependencies