Adds readinessProbe and livenessProbe to prometheus-adapter jsonnet

Problem: Currently the prometheus-adapter pods are restarted at the same
time even though the deployment is configured with strategy RollingUpdate.
This happens because the kubelet does not know when the prometheus-adapter
pods are ready to start receiving requests.

Solution: Add both readinessProbe and livenessProbe to the
prometheus-adapter, this way the kubelet will know when either the pod
stoped working and should be restarted or simply when it ready to start
receiving requests.

Issue: https://bugzilla.redhat.com/show_bug.cgi?id=2048333

jsonnet/kube-prometheus/components/prometheus-adapter.libsonnet

@@ -220,6 +220,26 @@ function(params) {
         '--tls-cipher-suites=' + std.join(',', pa._config.tlsCipherSuites),
       ],
       resources: pa._config.resources,
+      readinessProbe: {
+        httpGet: {
+          path: '/readyz',
+          port: 'https',
+          scheme: 'HTTPS',
+        },
+        initialDelaySeconds: 30,
+        periodSeconds: 5,
+        failureThreshold: 5,
+      },
+      livenessProbe: {
+        httpGet: {
+          path: '/livez',
+          port: 'https',
+          scheme: 'HTTPS',
+        },
+        initialDelaySeconds: 30,
+        periodSeconds: 5,
+        failureThreshold: 5,
+      },
       ports: [{ containerPort: 6443 }],
       volumeMounts: [
         { name: 'tmpfs', mountPath: '/tmp', readOnly: false },