Backslash in workflow commands

Hello,
I am having trouble having a backslash in my workflow command

 - name: Build_Package
        run : |
              echo Building a Release 
              bs="\\"
              dotnet pack "ClassLibrary${bs}ClassLibrary.csproj" -c Release --output=package_output

For some reason ‘\\’ is replaced by a ‘/’. However a ‘/’ designates a switch for the dotnet executable.
My full workflow script can be found @ Backslash Reproducer

What should I do to force a ‘\’ ?

Thanks

dotnet pack ClassLibrary\ClassLibrary.csproj -c Release --output=…/package_output

works fine. The issue was that I didn’t realise you must re-checkout the repository