Fixes for broken tox runs (#2053)

* order_utils.py: git rm package.json

This was used at one time, a long, long time ago, but is no longer used,
and its presence actually causes problems when trying to do, eg
`PKG=@0x/python-contract-wrappers yarn build` from within the
order_utils directory.

* order_utils.py: improve `./setup.py clean`

* python-packages: in tox, test, don't lint

* python-packages: update dev req's to fix tox runs

* contract_wrappers.py: post-publish version bump

python-packages/order_utils/setup.py

@@ -83,7 +83,10 @@ class CleanCommandExtension(clean):
     def run(self):
         """Run the regular clean, followed by our custom commands."""
         super().run()
+        rmtree("build", ignore_errors=True)
         rmtree("dist", ignore_errors=True)
+        rmtree(".coverage", ignore_errors=True)
+        rmtree(".eggs", ignore_errors=True)
         rmtree(".mypy_cache", ignore_errors=True)
         rmtree(".tox", ignore_errors=True)
         rmtree(".pytest_cache", ignore_errors=True)
@@ -180,6 +183,7 @@ setup(
     ],
     extras_require={
         "dev": [
+            "0x-contract-wrappers",
             "bandit",
             "black",
             "coverage",