PyTorch >= 1.7.0 and TensorFlow >= 2.4.0
# What does this PR do?

As discussed in #18817 we have decided that Transformers will support versions of PyTorch and TensorFlow for two years after their releases. As a result, Transformers can now assume a minimum version of 1.7.0 for PyTorch and 2.4.0 for TensorFlow. This PR enforces this in the setup and then simplifies a lot of code that was written to support older PyTorch versions.
_The documentation is not available anymore as the PR was closed or merged._<|||||>@sgugger curious what the reasoning was for blacklisting torch 1.12.0? I looked in  https://github.com/huggingface/transformers/issues/18817, but there's no info there for 1.12<|||||>That particular release broke weightnorm, and thus all audio models.