v0.16.139

Changes

build: simplify go commands (2) (#2452)
Use ./... instead of loop over packages.
Followup on #2449 and #2450
Also:

Docker image

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

docker run -it registry.opensource.zalan.do/teapot/skipper:v0.16.139 skipper --help
# arm64
docker run -it registry.opensource.zalan.do/teapot/skipper-arm64:v0.16.139 skipper --help
# arm v7 32bit
docker run -it registry.opensource.zalan.do/teapot/skipper-armv7:v0.16.139 skipper --help