Fix httpx support (select between allow_redirects/follow_redirects)

[immerrr]

This PR should fix the incompatibility introduced by the recent httpx release, when allow_redirects param was replaced with follow_redirects and default was changed from True to False.

[immerrr]

The CI build failed in my repo, due to what looks like a failure in pytest-httpbin:

https://github.com/immerrr/vcrpy/runs/4205197603?check_suite_focus=true#step:6:2872

I have submitted a PR to pytest-httpbin repo to fix this.

[immerrr]

I have submitted a temporary commit that points pytest-httpbin dependency to a branch in my repo with the fix:

https://github.com/immerrr/vcrpy/actions/runs/1459899288

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.82%. Comparing base (c3767c2) to head (bc2ce2e).
⚠️ Report is 332 commits behind head on master.
❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #621      +/-   ##
==========================================
- Coverage   89.85%   89.82%   -0.03%     
==========================================
  Files          27       27              
  Lines        1734     1730       -4     
  Branches      285      287       +2     
==========================================
- Hits         1558     1554       -4     
  Misses        140      140              
  Partials       36       36              

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

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[jairhenrique]

LGTM.

@kevin1024 can you review and bump a new version of pytest-httpbin kevin1024/pytest-httpbin#62

[immerrr]

Thank you @jairhenrique