fix: update the incorrect UI URL (#7183)

What changed?

Fix the incorrect UI URL in README.md.
Why?

The default UI URL is http://localhost:8088, not http://localhost:8080.
How did you test it?

Potential risks

Release notes

Documentation Changes

Author: ins-tril

README.md

@@ -26,7 +26,7 @@ Try out the sample recipes for [Go](https://github.com/cadence-workflow/cadence-
 
 3. Visit UI
 
-Visit http://localhost:8080 to check workflow histories and detailed traces.
+Visit http://localhost:8088 to check workflow histories and detailed traces.
 
 
 ### Client Libraries