[release-1.25] Remove deprecated nodeSelector label beta.kubernetes.io/os

[caroline-suse-rancher]

Problem:
The nodeSelector label beta.kubernetes.io/os in the CoreDNS deployment was deprecated in 1.14 and will likely be removed soon

Solution:
Change the nodeSelector to remove the beta

Backport for issue #6970

[fmoral2]

Validated on Version:

• [v1.25.8+k3s1]
• [v1.25.8+k3s-c25f611e] with commitId="c25f611eed749c15a51c6858480b84047974ab63"

Environment Details

Infrastructure
Cloud EC2 instance

Node(s) CPU architecture, OS, and Version:
Ubuntu 20.04

Cluster Configuration:
1 node

Config.yaml:

cat /etc/rancher/k3s/config,yaml
write-kubeconfig-mode: 644
token: secret
debug: true
cluster-init: true

Steps to reproduce the issue:

1. Copy config.yaml
2. Install k3s [v1.25.8+k3s1]
3. Validate coredns deployment "nodeSelector" is with label "beta.kubernetes.io/os=linux"

Steps to validate the fix:

1. Install version with commit ID c25f611
2. Validate coredns deployment "nodeSelector" is with label "kubernetes.io/os=linux"

Validation Results:

####### Issue #######
                       

Version of k3s: [v1.25.8+k3s1]


~$ k3s --version

k3s version v1.25.8+k3s1 (6c5ac022)
go version go1.19.7

$ kubectl -n kube-system get pod -l k8s-app=kube-dns -o=jsonpath='{$.items[0].spec.nodeSelector}'

{"beta.kubernetes.io/os":"linux"}


$ kubectl -n kube-system get deployment coredns -o yaml | grep -A1 'nodeSelector:'

   nodeSelector:
        beta.kubernetes.io/os: linux




========================================================================================================================   
               
                       
####### Fix ########
                          

Version of rkrs: [v1.25.8+k3s-c25f611e (c25f611e)]- CommitID = c25f611eed749c15a51c6858480b84047974ab63  


~$ k3s --version

k3s version v1.25.8+k3s-c25f611e (c25f611e)
go version go1.19.7


$ kubectl -n kube-system get deployment coredns -o yaml | grep -A1 'nodeSelector:
      nodeSelector:
        kubernetes.io/os: linux
              

$ kubectl -n kube-system get pod -l k8s-app=kube-dns -o=jsonpath='{$.items[0].spec.nodeSelector}'

{"kubernetes.io/os":"linux"}