v0.15.41

Changes

secrets: refactor file tests (#2252)
Refactors secrets file tests into multistep scenarios.
For #1858

Docker image

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

docker run -it registry.opensource.zalan.do/teapot/skipper:v0.15.41 skipper --help
# arm64
docker run -it registry.opensource.zalan.do/teapot/skipper-arm64:v0.15.41 skipper --help
# arm v7 32bit
docker run -it registry.opensource.zalan.do/teapot/skipper-armv7:v0.15.41 skipper --help