testing/soju: add cap_net_bind_service

This is necessary for the built-in identd, which needs to bind to
port 113.
8 jobs for !26372 with soju-setcap in 11 minutes and 28 seconds (queued for 9 seconds)
detached
Status Job ID Name Coverage
  Lint
passed #511012
docker-alpine x86_64
lint

00:00:20

 
  Build
passed #511017
docker-alpine ci-build aarch64
build-aarch64

00:04:59

passed #511019
docker-alpine ci-build armhf
build-armhf

00:04:14

passed #511018
docker-alpine ci-build armv7
build-armv7

00:04:23

passed #511016
docker-alpine ci-build ppc64le
build-ppc64le

00:06:06

passed #511015
docker-alpine ci-build s390x
build-s390x

00:02:13

passed #511014
docker-alpine ci-build x86
build-x86

00:03:06

passed #511013
docker-alpine ci-build x86_64
build-x86_64

00:02:14