Update Kubernetes client library

[csweichel]

We're still sitting on dependency of kubernetes/client-go version 1.15. We should update to at least 1.17, better yet 1.19.

Use https://github.com/gitpod-io/gitpod/blob/master/components/common-go/go-get-kubernetes.sh to update followed by leeway link.

This is directly influenced by #2657

[geropl]

Note: The move the 1.19 seems to be not very hard, as Gitpod mainly runs when switching to that master version, except one new field: Pod.PodSpec.PodSecurityContext.SeccompProfile

[corneliusludmann]

@csweichel Have you done something on this issue yet? I had noticed the other day that Gitpod does not work with k3s version v1.20.0+k3s2. After community members stumbled upon this as well, I took a look. It turns out that Gitpod does not work with Kubernetes 1.20 because the Kubernetes go client library needs to be updated. To verify this, I updated the client library to version v0.20.1 (1.20) (see 4f884be / clu/gitpod-k3s-v1-20—quick and dirty change, some places need probably be improved). With this change, Gitpod runs on Kubernetes 1.20 / latest k3s and our GCP dev-preview runs as well (at least workspaces start).

[csweichel]

@corneliusludmann did you use go-get-kubernetes.sh and leeway link or manually replace stuff in the go.mods?

[corneliusludmann]

I used go-get-kubernetes.sh and leeway link.