chore: remove typing-extensions dependency

[sauyon]

Remove dependency on typing-extensions.

Currently uses code from @bojiang's typing_utils for get_args and get_origin specifically for Python 3.7.

[pep8speaks]

Hello @sauyon, Thanks for updating this PR.

There are currently no PEP 8 issues detected in this PR. Cheers! 🍻

Comment last updated at 2022-08-09 00:25:55 UTC

[codecov]

Codecov Report

Merging #2879 (805a971) into main (03cf315) will increase coverage by 0.15%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #2879      +/-   ##
==========================================
+ Coverage   70.21%   70.37%   +0.15%     
==========================================
  Files         130      132       +2     
  Lines       10156    10530     +374     
==========================================
+ Hits         7131     7410     +279     
- Misses       3025     3120      +95     

Impacted Files	Coverage Δ
bentoml/_internal/runner/runnable.py	92.18% <100.00%> (-0.13%)	⬇️
bentoml/_internal/runner/runner.py	91.74% <100.00%> (-0.08%)	⬇️
bentoml/_internal/utils/formparser.py	20.00% <0.00%> (-57.94%)	⬇️
bentoml/_internal/runner/utils.py	90.16% <0.00%> (-1.70%)	⬇️
bentoml/_internal/context.py	85.45% <0.00%> (-1.59%)	⬇️
bentoml/_internal/frameworks/common/pytorch.py	72.63% <0.00%> (-0.49%)	⬇️
bentoml/_internal/runner/runner_handle/remote.py	88.17% <0.00%> (-0.13%)	⬇️
bentoml/_internal/server/service_app.py	87.94% <0.00%> (-0.09%)	⬇️
bentoml/__init__.py	100.00% <0.00%> (ø)
bentoml/_internal/server/__init__.py	63.30% <0.00%> (ø)
... and 17 more