pyproject.toml for version generation (#1534)

Instead of the usual setup.py.

Signed-off-by: Bernat Gabor <bgabor8@bloomberg.net>

Author: gaborbernat

pyproject.toml

@@ -1,11 +1,18 @@
 [build-system]
 requires = [
-    "setuptools >= 40.0.0",
-    "wheel >= 0.29.0",
-    "setuptools-scm >= 2, < 4",
+    "setuptools >= 41.0.0",
+    "wheel >= 0.30.0",
+    "setuptools_scm[toml]>=3.4",
 ]
 build-backend = 'setuptools.build_meta'
 
+[tool.setuptools_scm]
+write_to = "src/virtualenv/version.py"
+write_to_template = """
+\"\"\" Version information \"\"\"
+__version__ = "{version}"
+"""
+
 [tool.black]
 line-length = 120
 

setup.py

@@ -1,19 +1,3 @@
-# -*- coding: utf-8 -*-
-from __future__ import absolute_import, unicode_literals
-
-import textwrap
-
 from setuptools import setup
 
-setup(
-    use_scm_version={
-        "write_to": "src/virtualenv/version.py",
-        "write_to_template": textwrap.dedent(
-            """
-             # coding: utf-8
-             from __future__ import unicode_literals
-             __version__ = {version!r}
-             """
-        ).lstrip(),
-    }
-)
+setup()