Switch test manifests to apps/v1, remove beta workloads calls

hack/testdata/null-propagation/deployment-l1.yaml

@@ -1,8 +1,13 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: my-depl
+  labels:
+    l1: l1
 spec:
+  selector:
+    matchLabels:
+      l1: l1
   template:
     metadata:
       labels:

hack/testdata/null-propagation/deployment-l2.yaml

@@ -1,16 +1,16 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: my-depl
-  # We expect this field to be defaulted to the new label l2
   labels: null
 spec:
-  # We expect this field to be defaulted to the new label l2
-  selector: null
+  selector:
+    matchLabels:
+      l1: l1
   template:
     metadata:
       labels:
-        l2: l2
+        l1: l1
     spec:
       containers:
       - name: nginx