See if latest pyOpenSSL release fixes test failures against 1.1.1k

nixos/modules/overlays.nix

@@ -21,6 +21,8 @@ let
       # And explicitly configure it with our preferred version of Tahoe-LAFS.
       inherit tahoe-lafs;
     };
+
+    pyopenssl = python-self.callPackage ../pkgs/pyopenssl.nix { };
   };
 in
 self: super: {

nixos/pkgs/pyopenssl.nix

+{ fetchPypi, pyopenssl }:
+pyopenssl.overrideAttrs (old: {
+  version = "20.0.1";
+  inherit (old) name;
+  src = fetchPypi {
+    inherit name;
+    sha256 = "aeca66338f6de19d1aa46ed634c3b9ae519a64b458f8468aec688e7e3c20f201";
+  };
+})