Update .asf.yaml - fix spelling (apache#243)

Author: jbampton

.asf.yaml

@@ -32,7 +32,7 @@ github:
       required_status_checks:
         strict: false
       required_pull_request_reviews:
-        required_appoving_review_count: 1
+        required_approving_review_count: 1
       required_signatures: false
   enabled_merge_buttons:
     merge: false