Add whitespace after copyright header

Add an additional lines after the copyright header and before the
`package` declaration. This aligns with the style used by Spring
Framework.

Issue gh-8945

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/core/Saml2X509Credential.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.saml2.core;
 
 import java.security.PrivateKey;

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/credentials/Saml2X509Credential.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.saml2.credentials;
 
 import java.security.PrivateKey;

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationProvider.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.saml2.provider.service.authentication;
 
 import java.io.ByteArrayInputStream;