Use syntax updated with Python 3.8

[bryant1410]

Update the syntax with what Python 3.7 supports. I ran (and reviewed the changes):

pyupgrade $(find . -name "*.py" -type f) --py37-plus

I also manually changed 3 unnecessary list creations (one using a join and 2 using len).

[vturrisi]

@bryant1410 I've added your changes to #344 together with other changes.

[bryant1410]

Okay, I merged the latest changes and made sure it works the syntax is updated for Python 3.8 (nothing changed):

pyupgrade $(find . -name "*.py" -type f) --py38-plus

I also removed some remaining references to Python 3.7 and added explicit support for Python 3.10 and Python 3.11 (let's see if the tests pass to see if all the dependencies are correctly supported.).

And I updated some GitHub actions, hopefully the CI runs faster.

What do you think of these changes?

[codecov]

Codecov Report

Merging #343 (08e1089) into main (66cad5b) will decrease coverage by 0.03%.
The diff coverage is 0.00%.

Additional details and impacted files

Flag	Coverage Δ		*Carryforward flag
cpu	80.94% <0.00%> (ø)
dali	39.49% <ø> (-0.02%)	⬇️	Carriedforward from 66cad5b

*This pull request uses carry forward flags. Click here to find out more.

Impacted Files	Coverage Δ
solo/data/dali_dataloader.py	60.78% <0.00%> (-0.21%)	⬇️