docs: Add example on how to use list of object

examples/apply-setters-simple/.expected/diff.patch

@@ -1,29 +1,33 @@
 diff --git a/resources.yaml b/resources.yaml
-index b521905..0d10662 100644
+index 3dde2b6..47b7163 100644
 --- a/resources.yaml
 +++ b/resources.yaml
 @@ -3,7 +3,7 @@ kind: Deployment
- metadata:
-   name: my-nginx
- spec:
--  replicas: 4 # kpt-set: ${nginx-replicas}
-+  replicas: 3 # kpt-set: ${nginx-replicas}
-   selector:
-     matchLabels:
-       app: nginx
-@@ -14,7 +14,7 @@ spec:
-     spec:
-       containers:
-         - name: nginx
--          image: "nginx:1.16.1" # kpt-set: nginx:${tag}
-+          image: "nginx:1.16.2" # kpt-set: nginx:${tag}
-           ports:
-             - protocol: TCP
-               containerPort: 80
-@@ -24,5 +24,5 @@ kind: MyKind
- metadata:
-   name: foo
- environments: # kpt-set: ${env}
-+  - prod
-   - dev
--  - stage
+@@ -20,18 +20,20 @@
+            ports:
+              - protocol: TCP
+                containerPort: 80
+-@@ -24,5 +24,5 @@ kind: MyKind
++@@ -24,13 +24,13 @@ kind: MyKind
+  metadata:
+    name: foo
+  environments: # kpt-set: ${env}
+ +  - prod
+    - dev
+ -  - stage
+-@@ -24,5 +24,5 @@ kind: MyKind
++ ---
++ apiVersion: v1
++ kind: MyKind
+  metadata:
+    name: bar
+- environments: # kpt-set: ${env}
+-+  - key: some-other-key
+-     value: some-other-value
++ environments: # kpt-set: ${nested-env}
+ -  - key: some-key
+-     value: some-value
+\ No newline at end of file
++-    value: some-value
+++  - key: some-other-key
+++    value: some-other-value

examples/apply-setters-simple/README.md

@@ -22,12 +22,15 @@ desired value for the tagged field.
 apiVersion: v1
 kind: ConfigMap
 metadata:
-  name: apply-setters-fn-config
+  name: setters
 data:
-  replicas: "3"
-  role: |
-    - dev
+  env: |-
     - prod
+    - dev
+  nested-env: |-
+    - key: some-other-key
+      value: some-other-value
+  nginx-replicas: "3"
   tag: 1.16.2
 ```
 
@@ -43,7 +46,13 @@ $ kpt fn render apply-setters-simple
 
 1. Check the value of field `replicas` is set to `3` in `Deployment` resource.
 2. Check the value of field `image` is set to value `nginx:1.16.2` in `Deployment` resource.
-3. Check the value of field `environments` is set to value `[dev, prod]` in `MyKind` resource.
+3. Check the value of field `environments` is set to value `[dev, prod]` in `MyKind` resource with the name of `foo`.
+4. Check the value of field `environments` is set to value:
+```
+- key: some-other-key
+  value: some-other-value
+```
+in `MyKind` resource with the name of `bar`.
 
 #### Note:
 

examples/apply-setters-simple/resources.yaml

@@ -26,3 +26,11 @@ metadata:
 environments: # kpt-set: ${env}
   - dev
   - stage
+---
+apiVersion: v1
+kind: MyKind
+metadata:
+  name: bar
+environments: # kpt-set: ${nested-env}
+  - key: some-key
+    value: some-value

examples/apply-setters-simple/setters.yaml

@@ -6,5 +6,8 @@ data:
   env: |-
     - prod
     - dev
+  nested-env: |-
+    - key: some-other-key
+      value: some-other-value
   nginx-replicas: "3"
   tag: 1.16.2