Pre Kubernetes v1.20, exec livenessprobes `timeoutSeconds` wasn't functional, and defaults to 1 second. The livenessprobe for the scheduler, however, takes longer than 1 second to finish so the scheduler will have consistent livenessprobe failures when running on v1.20.

> Before Kubernetes 1.20, the field timeoutSeconds was not respected for exec probes: probes continued running indefinitely, even past their configured deadline, until a result was returned.

```
...
  Warning  Unhealthy  23s    kubelet            Liveness probe failed:
```

https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/#configure-probes

**Kubernetes version**: v1.20.2

**What happened**:

Livenessprobe failures keeps restarting the scheduler due to timing out.

**What you expected to happen**:

Livenessprobe succeeds.

**How to reproduce it**:

Deploy the helm chart on v1.20+ with the default livenessprobe `timeoutSeconds` of 1 and watch the scheduler livenessprobe fail.

chart/tests/test_scheduler.py
docs = render_chart(
            values={
                "executor": "CeleryExecutor",
                "scheduler": {
                    "extraVolumes": [{"name": "test-volume", "emptyDir": {}}],
                    "extraVolumeMounts": [{"name": "test-volume", "mountPath": "/opt/test"}],
                },
            },
            show_only=["templates/scheduler/scheduler-deployment.yaml"],
        )
        assert "test-volume" == jmespath.search("spec.template.spec.volumes[1].name", docs[0])
        assert "test-volume" == jmespath.search(
            "spec.template.spec.containers[0].volumeMounts[3].name", docs[0]
        )
    def test_should_create_valid_affinity_tolerations_and_node_selector(self):
        docs = render_chart(
            values={
                "scheduler": {
                    "affinity": {
                        "nodeAffinity": {
                            "requiredDuringSchedulingIgnoredDuringExecution": {
                                "nodeSelectorTerms": [
                                    {
                                        "matchExpressions": [
                                            {"key": "foo", "operator": "In", "values": ["true"]},
                                        ]
                                    }