Remove pipenv from extra_tests/README.md

Author: youknowone

extra_tests/README.md

@@ -6,13 +6,12 @@ directory contains snippets for use in benchmarking RustPython's performance.
 
 ## Setup
 
-Our testing depends on [pytest](https://pytest.org), which you can either
-install globally using pip or locally using our
-[pipenv](https://docs.pipenv.org).
+Our testing depends on [pytest](https://pytest.org), which you can install
+using pip.
 
 ## Running
 
-Simply run `pytest` in this directory, and the tests should run (and hopefully
+Simply run `pytest -v` in this directory, and the tests should run (and hopefully
 pass). If it hangs for a long time, that's because it's building RustPython in
 release mode, which should take less time than it would to run every test
 snippet with RustPython compiled in debug mode.