Thanks for reaching out. That version of the Azure Devops step will not work with Octopus 2.0.135. That version of Octopus is over 4yo now and we are no longer providing support for it.
Is there a reason why you are downloading such an old version instead of 2019.*?
If you want to keep using 2.0.135, you’ll need to use the Azure Devops built-in step that executes Nuget.exe push to push your packages to the Octopus built-in repository.