testing/k3s: security fixes CVE-2020-8555 and CVE-2020-10749

- Upgrade to 1.18.3.1
- Ref https://github.com/rancher/k3s/releases
7 jobs for !8704 with k3s in 7 minutes and 18 seconds
detached
Status Job ID Name Coverage
  Lint
passed lint #132024
docker-alpine x86_64

00:00:24

 
  Build
passed build-aarch64 #132029
docker-alpine ci-build aarch64

00:04:42

passed build-armv7 #132030
docker-alpine ci-build armv7

00:06:11

passed build-ppc64le #132028
docker-alpine ci-build ppc64le

00:06:52

passed build-s390x #132027
docker-alpine ci-build s390x

00:03:09

passed build-x86 #132026
docker-alpine ci-build x86

00:03:18

passed build-x86_64 #132025
docker-alpine ci-build x86_64

00:02:59