Additional SSL options are being discarded ...

There are several optional setting that could be passed along to the underlying erlang ssl system:

https://elixirforum.com/t/making-ssl-tests-all-pass-for-phoenix-lets-encrypt/3507/15

https: [
    port: System.get_env("APP_HTTPS_PORT") || "${APP_HTTPS_PORT}",
    keyfile: System.get_env("APP_SSL_KEY_PATH") || "${APP_SSL_KEY_PATH}",
    certfile: System.get_env("APP_SSL_CERT_PATH") || "${APP_SSL_CERT_PATH}",
    cacertfile: System.get_env("APP_SSL_INTERMEDIATE_CERT_PATH") || "${APP_SSL_INTERMEDIATE_CERT_PATH}",
    dhfile: System.get_env("APP_SSL_DHPARAMS_PATH") || "${APP_SSL_DHPARAMS_PATH}",
    versions: [:'tlsv1.2'],
    ciphers: ~w(
      ECDHE-ECDSA-AES128-GCM-SHA256
      ECDHE-ECDSA-AES256-GCM-SHA384
      ECDHE-ECDSA-AES128-SHA
      ECDHE-ECDSA-AES256-SHA
      ECDHE-ECDSA-AES128-SHA256
      ECDHE-ECDSA-AES256-SHA384
      ECDHE-RSA-AES128-GCM-SHA256
      ECDHE-RSA-AES256-GCM-SHA384
      ECDHE-RSA-AES128-SHA
      ECDHE-RSA-AES256-SHA
      ECDHE-RSA-AES128-SHA256
      ECDHE-RSA-AES256-SHA384
      DHE-RSA-AES128-GCM-SHA256
      DHE-RSA-AES256-GCM-SHA384
      DHE-RSA-AES128-SHA
      DHE-RSA-AES256-SHA
      DHE-RSA-AES128-SHA256
      DHE-RSA-AES256-SHA256
    )c,
    secure_renegotiate: true,
    client_renegotiation: false,
    reuse_sessions: true,
    honor_cipher_order: true,
    max_connections: :infinity
  ],

Elli discards the rest of the Optsand only keeps two:

elli/src/elli.erl

Lines 135 to 137 in d22bc09

    
           SSLSockOpts    = ?IF(UseSSL, 
        
                                [{keyfile, KeyFile}, {certfile, CertFile}], 
        
                                []),

I suggest we pass through all additional params set by the user.

This PR attempts to fix: #106

Regards.

Thanks for the report, and the PR!

	SSLSockOpts = ?IF(UseSSL,
	[{keyfile, KeyFile}, {certfile, CertFile}],
	[]),