set validationInterval to 5 seconds

apollo-common/src/main/resources/application.properties

@@ -4,6 +4,7 @@ spring.http.converters.preferred-json-mapper=gson
 spring.datasource.testWhileIdle=true
 spring.datasource.testOnBorrow=true
 spring.datasource.validationQuery=SELECT 1
+spring.datasource.validationInterval=5000
 spring.datasource.initSQL=set names utf8mb4
 
 # Naming strategy