chore(deps-dev): fix typing-extensions version

[PrettyWood]

Change Summary

typing-extensions has been bumped to 3.4.7.3 in #2216 to have a good DefaultDict for python 3.8 and less.
But now when running make install and make test, the TypedDict related tests fail because the installed
version is 3.4.7, which does not have TypedDict backport.
This fixes this

Related issue number

Checklist

• Unit tests for the changes exist
• Tests pass on CI and coverage remains at 100%
• Documentation reflects the changes where applicable
• changes/<pull request or issue id>-<github username>.md file added describing change
  (see changes/README.md for details)

[codecov]

Codecov Report

Merging #2361 (d995d45) into master (13928e5) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2361   +/-   ##
=======================================
  Coverage   99.97%   99.97%           
=======================================
  Files          23       23           
  Lines        4496     4496           
  Branches      909      909           
=======================================
  Hits         4495     4495           
  Misses          1        1           

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[samuelcolvin]

🙏 thank you.