Min TLS version configuration is not considered

Summary

The configuration introduced by !46 (merged) looks to not be considered.

Steps to reproduce

1. Use a basic router configuration with a working SSL host
2. Analyse the SSL state with a tool: https://www.ssllabs.com/ssltest/analyze.html?d=tld.nexylan.dev

What is the current bug behavior?

TLS <= 1.1 is still supported.

What is the expected correct behavior?

TLS >=1.2 only should be supported, as described on the configuration: https://gitlab.com/nexylan/docker/router/blob/efcfdc742893fd9c9f8a5aa3b5db7180af90956e/rootfs/etc/traefik.toml#L4

Relevant information

The configuration is correctly placed at /etc/traefik.toml loaded by this option: https://gitlab.com/nexylan/docker/router/blob/55ae561ecdfe8cd34a87ce43d74d359a27054fa3/rootfs/entrypoint.sh#L17

Bug resolution

Possible workarounds

Use this kind of label to raise the support level (example with >=1.3):

"traefik.http.routers.[ROUTER_NAME].tls.options": "mintls13"

Possible fixes

N/A