Merge pull request #6597 from segmentio/bill-wilkin-patch-8

Update index.md

Author: forstisabella

src/connections/destinations/catalog/actions-google-analytics-4/index.md

@@ -214,6 +214,7 @@ Google reserves certain event names, parameters, and user properties. Google sil
 - fields or events with reserved names
 - fields with a number as the key
 - fields or events with a dash (-) character in the name
+- property names with capital letters
 
 ### Verifying Event Meet GA4's Measurement Protocol API
 **Why are the events returning an error _Param [PARAM] has unsupported value._?**