Add a minimal pyproject.toml following pep-0518

renefritze · renefritze · commit f084c3d6299a · 2019-01-22T10:22:57.000+01:00
This allows docopt to be installed via pip if setuptools
is not yet installed in the environment.
diff --git a/pyproject.toml b/pyproject.toml
@@ -0,0 +1,3 @@
+[build-system]
+requires = ['setuptools', 'wheel']
+
