HADOOP-18630. Add gh-pages in asf.yaml to deploy the current trunk doc (#5393). Contributed by Simhadri Govindappa.

Signed-off-by: Ayush Saxena <ayushsaxena@apache.org>

.asf.yaml

@@ -14,6 +14,8 @@
 # limitations under the License.
 
 github:
+  ghp_path: /
+  ghp_branch: gh-pages
   enabled_merge_buttons:
     squash: true
     merge: false