Python 3.10 support

[gabrielcnr]

I tried to create a fresh new environment for Python 3.10 with all the listed dependencies for elegy and it seems that all of them are already available for python 3.10:

• cloudpickle
• tensorboardx
• wandb
• treex

Since elegy doesn't seem to have any compiled extensions, I was wondering if there is anything else forcing the constraint:

python = ">=3.7,<3.10"

I'd really like to use elegy in my Python 3.10 environment. Would it be possible to release a new version with that constraint updated to:

python = ">=3.7,<3.11"

Thank you.