default.nix: switch openssl dependency to 1.0.0 as `cryptography` has trouble compiling against 1.1.0 on darwin
default.nix: switch openssl dependency to 1.0.0 as `cryptography` has trouble compiling against 1.1.0 on darwin

alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend