Fix the wrong env in the readme file

Author: saragluna

azure-spring-apps-enterprise/README.md

@@ -1903,7 +1903,7 @@ cd apps/acme-assist
         --build-env BP_JVM_VERSION=17 \
         --env \
             SPRING_AI_AZURE_OPENAI_ENDPOINT=${SPRING_AI_AZURE_OPENAI_ENDPOINT} \
-            SPRING_AI_AZURE_OPENAI_API_KEY=${SPRING_AI_AZURE_OPENAI_API_KEY}
+            SPRING_AI_AZURE_OPENAI_API_KEY=${SPRING_AI_AZURE_OPENAI_APIKEY}
     ```
 
 1. Test the `acme-fitness` application in the browser again. Go to `ASK TO FITASSIST` and converse with the assistant, e.g.