Update copyright of changed files

See gh-44413

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/appendix/configurationmetadata/annotationprocessor/automaticmetadatageneration/MyServerProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/appendix/configurationmetadata/annotationprocessor/automaticmetadatageneration/nestedproperties/MyServerProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.