v0.13.67

Changes

Fix anchor links in documentation (#1790)
The headings are all converted to lowercase when they are turned into anchors so we also need to use lowercase when referencing them as internal skip links.

Docker image

Docker image is available in Zalando's Open Source registry:

docker run -it registry.opensource.zalan.do/teapot/skipper:v0.13.67 skipper --help
# arm64
docker run -it registry.opensource.zalan.do/teapot/skipper-arm64:v0.13.67 skipper --help
# arm v7 32bit
docker run -it registry.opensource.zalan.do/teapot/skipper-armv7:v0.13.67 skipper --help