Varnish 6.6.1-r0

The docker images livingdocs/varnish:6.6.1-r0 and livingdocs/varnish:latest got pushed

Changelog

• 💥 Remove all environment variables
• 💥 Remove the curl vmod as it's not maintained and the build fails
• 💥 Change the varnish port to 8080 and run as varnish user (non-root)
• 🍬 Upgrade to varnish 6.6.1, that includes the accept vmod
• 🍬 Support stale-if-error directive in Cache-Control header
• 🍬 Support X-Cache-Ban Header additionally to X-Cache-Tags during BAN requests
• 🎁 An improved templating setup
• 🎁 Hot reloading by watching for file changes
• 🎁 Config reloads using SIGHUP signal
• 🎁 Automatic dns reloads
• 🎁 Automatically apply varnish parameters on startup or config change