six: expect specific version

since we use features introduced in 1.9.0, we require it for
installation/use

also add test coverage to ensure we update that version when we need
something newer

1 files changed, 1 insertions, 1 deletions

diff --git a/setup.py b/setup.py
index c0959d4..13c9164 100755
--- a/setup.py
+++ b/setup.py
@@ -40,5 +40,5 @@ setup(name="ecdsa",
           "Programming Language :: Python :: 3.7",
           "Programming Language :: Python :: 3.8",
       ],
-      install_requires=['six'],
+      install_requires=['six>=1.9.0'],
       )