Update k8s client and release k8s lock gracefully

[ChrsMark]

What does this PR do?

Updates k8s go client to utilise a fix so as to gracefully release leader lock.

Why is it important?

To release the leader lease gracefully and make it instantly available for other candidates.

Related issues

• Closes [Kubernetes] Release leader lock on shutdown for faster failover #21952
• Relates Kubernetes leaderelection improvements #21896

How to test this PR locally

1. Deploy a k8s cluster using kind: kind create cluster --config kind-mutly.yaml

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
- role: worker
- role: worker

2. Deploy metricbeat with the latest change included using 7.11.0-SNAPSHOT

metricbeat-kubernetes-leader.7.11.yaml.txt

3. Follow the logs of the 2 daemonset pods and kill the one holding the lease. Verify that no errors occur and that the lease was gained by the other Pod.

4. Verify that basic autodiscovery works along with metadata:
   nats.yaml.txt

[elasticmachine]

Pinging @elastic/integrations-platforms (Team:Platforms)

[elasticmachine]

💚 Build Succeeded

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Build stats

• Build Cause: Pull request #22919 updated

• Start Time: 2020-12-08T12:29:09.250+0000

• Duration: 101 min 40 sec

Test stats 🧪

Test	Results
Failed	0
Passed	17359
Skipped	1373
Total	18732

💚 Flaky test report

Tests succeeded.

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Test stats 🧪

Test	Results
Failed	0
Passed	17359
Skipped	1373
Total	18732

[jsoriano]

Thanks @ChrsMark for keeping an eye on this!