v2.12.0 -> v2.12.1

Refactors

• cea7734 ci: remove travis; add badge

Fixes

• e559768 charts: remove b64enc from dhparam

Maintenance

• b8560e0 Dockerfile: update nginx to 1.11.13
• 21aa475 Dockerfile: update nginx to 1.12.0 stable
• 2f7705c Dockerfile: update nginx to 1.13.0