Add namespace for config map and secret generators

pkg/commands/build/testdata/testcase-generators-namespace/in/kustomization.yaml

@@ -0,0 +1,19 @@
+configMapGenerator:
+- name: the-non-default-namespace-map
+  namespace: non-default
+  literals:
+  - altGreeting=Good Morning from non-default namespace!
+  - enableRisky="false"
+- name: the-map
+  literals:
+  - altGreeting=Good Morning from default namespace!
+  - enableRisky="false"
+
+secretGenerator:
+- name: the-non-default-namespace-secret
+  namespace: non-default
+  commands:
+    password.txt: "cat password.txt"
+- name: the-secret
+  commands:
+    password.txt: "cat password.txt"