aiohttp build fails (can't find idna-ssl)

[WhittlesJr]

Issue description

Collecting idna-ssl>=1.0.0 (from aiohttp==2.3.10)
  Could not find a version that satisfies the requirement idna-ssl>=1.0.0 (from aiohttp==2.3.10) (from versions: )                           
No matching distribution found for idna-ssl>=1.0.0 (from aiohttp==2.3.10)                                                                    
builder for '/nix/store/23m219pswwvkksv6gswa0137c8j6jrl7-python3.7-aiohttp-2.3.10.drv' failed with exit code 1                               

I have a potential fix. PR incoming.

Steps to reproduce

I discovered this when trying to install appdaemon.

Technical details

• system: "x86_64-linux"
• host os: Linux 4.14.81, NixOS, 19.03.git.3a393ee (Koi)
• multi-user?: no
• sandbox: yes
• version: nix-env (Nix) 2.1.3
• channels(root): "nixos-19.03pre159472.80738ed9dc0"
• nixpkgs: /home/alexj/Documents/Repositories/nixpkgs