Replace deprecated tox.ini option

[emsearcy]

Description

I have fixed a broken option in the tox.ini file. This option was replaced in 2020, deprecated, and eventually removed in tox 4. The correct option already appears elsewhere in this tox.ini file.

https://tox.wiki/en/3.18.1/changelog.html#v3-18-0-2020-07-23

This fix is necessary to run tox -e doc per the README.md instructions on tox version 4.

Issue reference

Skipped due to minor nature of issue; no actual code changes.

Here was the build error from tox -e doc:

[...]
doc: commands[0]> sphinx-apidoc -E -o docs/actor dapr/actor
doc: commands[1]> sphinx-apidoc -E -o docs/clients dapr/clients
doc: commands[2]> sphinx-apidoc -E -o docs/proto dapr/proto
doc: commands[3]> sphinx-apidoc -E -o docs/serializers dapr/serializers
doc: commands[4]> make html -C docs
doc: failed with make is not allowed, use allowlist_externals to allow it
  doc: FAIL code 1 (25.60 seconds)
  evaluation failed :( (25.65 seconds)

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

I'm assuming all of the above are n/a -- there are no meaningful changes to the codebase itself.

[elena-kolevska]

Thanks for your contribution @emsearcy!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.03%. Comparing base (bffb749) to head (48c5cf0).
Report is 11 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #762      +/-   ##
==========================================
- Coverage   86.63%   86.03%   -0.60%     
==========================================
  Files          84       87       +3     
  Lines        4473     4783     +310     
==========================================
+ Hits         3875     4115     +240     
- Misses        598      668      +70     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[marcduiker]

@holopin-bot @emsearcy Thanks Eric! Here's a digital badge as a small token of appreciation.

[holopin-bot]

Congratulations @emsearcy, the maintainer of this repository has issued you a badge! Here it is: https://holopin.io/claim/cm5qypmta52410clb7kudfcu0

This badge can only be claimed by you, so make sure that your GitHub account is linked to your Holopin account. You can manage those preferences here: https://holopin.io/account.
Or if you're new to Holopin, you can simply sign up with GitHub, which will do the trick!