Boa tarde, poderiam me ajudar nesse erro..

Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value 'Hora oficial do Brasil' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59) at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:83) at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:128) at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2201) at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2225) at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1391) at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:993) at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:852)

MINHA CLASSE DE PERSISTÊNCIA

<!-- unidade de persistencia com o nome financas -->
<persistence-unit name="financas">

    <!-- Implementação do JPA, no nosso caso Hibernate -->
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

    <!-- Aqui são listadas todas as entidades -->
    <class>br.com.caelum.financas.modelo.Conta</class>

    <properties>

        <!-- Propriedades JDBC -->
        <property name="javax.persistence.jdbc.driver"
            value="com.mysql.jdbc.Driver" />
        <property name="javax.persistence.jdbc.url"
            value="jdbc:mysql://localhost:financas/>
        <property name="javax.persistence.jdbc.user" value="root" />
        <property name="javax.persistence.jdbc.password"
            value="123456" />

        <property name="hibernate.dialect" 
            value="org.hibernate.dialect.MySQL5InnoDBDialect" />

        <property name="hibernate.hbm2ddl.auto" value="update" />
        <property name="hibernate.show_sql" value="true" />
        <property name="hibernate.format_sql" value="true" />
    </properties>
</persistence-unit>