Add documentation for running upgrade samples
This MR ads a paragraph on how to run r21.9 upgrade samples with the TDD in the Advanced Usage section of the doc (https://training-dataset-dumper.docs.cern.ch/advanced_usage/).
This MR ads a paragraph on how to run r21.9 upgrade samples with the TDD in the Advanced Usage section of the doc (https://training-dataset-dumper.docs.cern.ch/advanced_usage/).