chore: param enum usage example for stepaction

add param enum usage with step action to document the usage.

Author: waveywaves

examples/v1/taskruns/beta/stepaction-params.yaml

@@ -25,6 +25,9 @@ spec:
         key1: "step-action default key1"
         key2: "step-action default key2"
         key3: "step-action default key3"
+    - name: enum-param
+      enum: ["def1", "def2", "def3"]
+      default: "def1"
   env:
     - name: arrayparam0
       value: $(params.array-param[0])
@@ -40,10 +43,16 @@ spec:
       value: $(params.object-param.key2)
     - name: objectparamkey3
       value: $(params.object-param.key3)
+    - name: enumparamkey1
+      value: $(params.enum-param.v1)
+    - name: enumparamkey2
+      value: $(params.enum-param.v2)
+    - name: enumparamkey3
+      value: $(params.enum-param.v3)
   image: mirror.gcr.io/ubuntu
   script: |
     #!/bin/bash
-    ARRAYVALUE=("${arrayparam0}" "${arrayparam1}" "${arrayparam2}" "${stringparam}" "${objectparamkey1}" "${objectparamkey2}" "${objectparamkey3}")
+    ARRAYVALUE=("${arrayparam0}" "${arrayparam1}" "${arrayparam2}" "${stringparam}" "${objectparamkey1}" "${objectparamkey2}" "${objectparamkey3} "${enumparamkey1}" "${enumparamkey2}" "${enumparamkey3}")
     ARRAYEXPECTED=("taskrun" "array" "param" "taskrun stringparam" "taskspec default key1" "taskrun key2" "step-action default key3")
     for i in "${!ARRAYVALUE[@]}"; do
         VALUE="${ARRAYVALUE[i]}"
@@ -73,6 +82,10 @@ spec:
     - name: objectparam
       value:
         key2: "taskrun key2"
+    - name: enumparam
+      enum: ["enum1", "enum2", "enum3"]
+      default: "enum1"
+
   TaskSpec:
     params:
       - name: objectparam
@@ -95,3 +108,5 @@ spec:
             value: $(params.arrayparam[*])
           - name: object-param
             value: $(params.objectparam[*])
+          - name: enum-param
+            value: $(params.enumparam[*])