We need to call sphinx-build indirectly so tox-current-env is able to find it
and to run the proper version.

--- sphinx_issues-5.0.0/tests/test_sphinx_issues.py.orig
+++ sphinx_issues-5.0.0/tests/test_sphinx_issues.py
@@ -312,7 +312,9 @@
     """Ensure that a simulated complete sphinx run works as expected"""
     subprocess.run(
         [
-            Path(sys.executable).parent.joinpath("sphinx-build"),
+            Path(sys.executable).parent.joinpath("python"),
+            "-m",
+            "sphinx.cmd.build",
             "-b",
             "html",
             "-W",  # turn warnings into errors