v0.13.13

Changes

Removes Redis ring availability check (#1691)
Removes ring availability check from ratelimiter constructor
in order not to block requests when ring is not available.
Fixes #1690

Docker image

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

docker run -it registry.opensource.zalan.do/teapot/skipper:v0.13.13 skipper --help
# arm64
docker run -it registry.opensource.zalan.do/teapot/skipper-arm64:v0.13.13 skipper --help
# arm v7 32bit
docker run -it registry.opensource.zalan.do/teapot/skipper-armv7:v0.13.13 skipper --help