adding POST role mapping test

Signed-off-by: Tokesh <[email protected]>

tests/default/indices/mapping/index.yaml

@@ -145,4 +145,23 @@ chapters:
     response:
       status: 200
       payload:
-        acknowledged: true
+        acknowledged: true
+  - synopsis: Add or update mapping using POST method.
+    path: /{index}/_mapping
+    method: POST
+    parameters:
+      index: movies
+      allow_no_indices: false
+      ignore_unavailable: false
+      expand_wildcards: open
+    request:
+      payload:
+        properties:
+          actor:
+            type: text
+          rating:
+            type: float
+    response:
+      status: 200
+      payload:
+        acknowledged: true