Attempt 2 reduce cache size

Author: mcbarton

.github/workflows/ci.yml

@@ -366,7 +366,7 @@ jobs:
           cmake --build . --target clang clang-repl lld --parallel ${{ env.ncpus }}
         fi
         cd ../
-        rm -rf $(find . -maxdepth 1 ! -name "build" ! -name ".")
+        rm -rf $(find . -maxdepth 1 ! -name "build" ! -name "llvm" ! -name "clang" ! -name ".")
         cd ../
 
     - name: Build LLVM/Cling on Windows systems if the cache is invalid