Allow pytest 6.2.4

I confirmed that tests pass with pytest 6.2.4 by running
  tox -r -e py310,py311 --force-dep pytest==6.2.4
Running the corresponding command for pytest 6.2.3 does not pass, so
this is the lowest version we can support on Python 3.10+.

Author: diazona

tox.ini

@@ -14,8 +14,14 @@ deps =
     # with major versions that haven't been released yet. Each time a new major
     # version of pytest is released, once it's confirmed to work with this
     # package, we should bump this limit to the next major version.
+    #
+    # The lower bounds come from testing with different pytest versions using
+    # tox's --force-dep option to find the earliest versions of pytest that are
+    # known to work. If you add code that breaks with an old version of pytest,
+    # feel free to raise these bounds to represent the earliest version that
+    # works with your code.
     pytest >=4, <8; python_version<'3.10'
-    pytest >=6.2.5, <8; python_version>='3.10'
+    pytest >=6.2.4, <8; python_version>='3.10'
     pytest-cov
     six
     requests