Fix missing six requirement (#132)

noyainrain · web-flow · commit 51f1f9e3200f · 2021-02-19T11:03:23.000-08:00
diff --git a/requirements.txt b/requirements.txt
@@ -1,4 +1,5 @@
 cryptography>=2.6.1
 http-ece>=1.1.0
 requests>=2.21.0
+six>=1.15.0
 py-vapid>=1.7.0
