buildx failed with: ERROR: failed to solve: process "/bin/sh -c GOOS=$TARGETOS GOARCH=$TARGETARCH go build -ldflags=\" -X 'github.com/steadybit/extension-kit/extbuild.ExtensionName=${NAME}' -X 'github.com/steadybit/extension-kit/extbuild.Version=${VERSION}' -X 'github.com/steadybit/extension-kit/extbuild.Revision=${REVISION}'\" -o ./extension" did not complete successfully: exit code: 1