Merge branch '6.4' into 7.0

* 6.4:
  [SecurityBundle] Deprecate the `require_previous_session` config option
  fix version in changelog file
  [Mailer] update Brevo SMTP host
  change default doctrine DBAL provider to XML attribute

Author: fabpot

Resources/config/schema/symfony-1.0.xsd

@@ -337,7 +337,6 @@
             <xsd:element name="default-psr6-provider" type="xsd:string" minOccurs="0" maxOccurs="1" />
             <xsd:element name="default-redis-provider" type="xsd:string" minOccurs="0" maxOccurs="1" />
             <xsd:element name="default-memcached-provider" type="xsd:string" minOccurs="0" maxOccurs="1" />
-            <xsd:element name="default-doctrine-dbal-provider" type="xsd:string" minOccurs="0" maxOccurs="1" />
             <xsd:element name="default-pdo-provider" type="xsd:string" minOccurs="0" maxOccurs="1" />
             <xsd:element name="pool" type="cache_pool" minOccurs="0" maxOccurs="unbounded" />
         </xsd:sequence>
@@ -349,6 +348,7 @@
         <xsd:attribute name="default-redis-provider" type="xsd:string" />
         <xsd:attribute name="default-memcached-provider" type="xsd:string" />
         <xsd:attribute name="default-pdo-provider" type="xsd:string" />
+        <xsd:attribute name="default-doctrine-dbal-provider" type="xsd:string" />
         <xsd:attribute name="prefix-seed" type="xsd:string" />
     </xsd:complexType>