K8SPG-543: fix panic (#708)

* K8SPG-543: fix panic

https://perconadev.atlassian.net/browse/K8SPG-543

* add test

---------

Co-authored-by: Viacheslav Sarzhan <[email protected]>

Author: pooknull

pkg/apis/pgv2.percona.com/v2/perconapgcluster_types.go

@@ -183,6 +183,10 @@ func (cr *PerconaPGCluster) Default() {
 		cr.Spec.InstanceSets[i].Metadata.Labels[LabelOperatorVersion] = cr.Spec.CRVersion
 	}
 
+	if cr.Spec.Proxy == nil {
+		cr.Spec.Proxy = new(PGProxySpec)
+	}
+
 	if cr.Spec.Proxy.PGBouncer == nil {
 		cr.Spec.Proxy.PGBouncer = new(PGBouncerSpec)
 	}

pkg/apis/pgv2.percona.com/v2/perconapgcluster_types_test.go

@@ -0,0 +1,10 @@
+package v2
+
+import (
+	"testing"
+)
+
+func TestPerconaPGCluster_Default(t *testing.T) {
+	// cr.Default() should not panic on PerconaPGCluster with empty fields
+	new(PerconaPGCluster).Default()
+}