ci: drop auto-merge, request review from host-sdk-team instead

Author: filvecchiato

.github/workflows/number-rfc.yml

@@ -126,5 +126,5 @@ jobs:
             --title "ci: update RFC index" \
             --body "Auto-generated by the number-rfc workflow." \
             --head "$BRANCH" \
-            --base main
-          gh pr merge "$BRANCH" --auto --squash
+            --base main \
+            --reviewer paritytech/host-sdk-team