Since zope-testrunner is invoked with python3 -sP on Fedora,
it seems to cause an issue because lazr.delegates is in system sitelib
but lazr.config is in buildroot.

On EPEL 9, where the shebang is python3 -s, this works.

Sidestep the issue by invoking python -sm zope.testrunner rather than
invoking zope-testrunner via its wrapper

h/t churchyard
```
Test-module import failures:
Module: lazr.config.tests.test_config
ModuleNotFoundError: No module named 'lazr.config'
Module: lazr.config.tests.test_docs
ModuleNotFoundError: No module named 'lazr.config'
Test-modules with import problems:
  lazr.config.tests.test_config
  lazr.config.tests.test_docs
Total: 0 tests, 0 failures, 2 errors and 0 skipped in 0.000 seconds.
```
--- a/tox.ini
+++ b/tox.ini
@@ -16,7 +16,7 @@ skip_missing_interpreters = True
 deps =
     zope.testrunner
 commands =
-    zope-testrunner --test-path src --tests-pattern ^tests {posargs}
+    python -sm zope.testrunner --test-path src --tests-pattern ^tests {posargs}
 
 [testenv:pre-commit]
 # necessary to build the woke linter