Update MP Database archetype README to use "type" not "idType" (helidon-io#2329)

Author: barchetta

archetypes/database-mp/src/main/resources/README.md.mustache

@@ -14,12 +14,12 @@ java -jar target/{{artifactId}}.jar
 
 ```
 curl -X GET http://localhost:8080/pokemon
-[{"id":1,"idType":12,"name":"Bulbasaur"}, ...]
+[{"id":1,"type":12,"name":"Bulbasaur"}, ...]
 
 curl -X GET http://localhost:8080/type
 [{"id":1,"name":"Normal"}, ...]
 
-curl -H "Content-Type: application/json" --request POST --data '{"id":100, "idType":1, "name":"Test"}' http://localhost:8080/pokemon
+curl -H "Content-Type: application/json" --request POST --data '{"id":100, "type":1, "name":"Test"}' http://localhost:8080/pokemon
 ```
 
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