SLING-8311 - Investigate creating a Sling CLI tool for development task automation

Update README for update-local-site
diff --git a/README.md b/README.md
index 45336b1..9dbad6e 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,10 @@
 Generating a release vote result email
 
     docker run --env-file=./docker-env apache/sling-cli release tally-votes $STAGING_REPOSITORY_ID
+    
+Generating the website update (only diff for now)
+
+	docker run --env-file=docker-env apache/sling-cli release update-local-site $STAGING_REPOSITORY_ID
 
 ## Assumptions