Work around setuptools 60 release in test.
The release added a warning that trips up a test. Pin low to avoid this
since setuptools version is incidental to the test.
See:
@@ -1566,6 +1566,7 @@ def test_requirement_file_from_url(tmpdir):
with open(constraints, "w") as fp:
print("translate>=3.2.1,<3.6.0", file=fp)
print("protobuf<=3.17.3", file=fp)
+ print("setuptools<60", file=fp)
pex_file = os.path.join(str(tmpdir), "pex")
