Update copyright year to 2021.

Closes #2133

Author: mp911de

src/main/asciidoc/index.adoc

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2020 the original author or authors.
+ * Copyright 2016-2021 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.

src/main/java/org/springframework/data/jpa/convert/QueryByExamplePredicateBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2020 the original author or authors.
+ * Copyright 2014-2021 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.

src/main/java/org/springframework/data/jpa/convert/threeten/Jsr310JpaConverters.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2020 the original author or authors.
+ * Copyright 2015-2021 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.

src/main/java/org/springframework/data/jpa/convert/threetenbp/ThreeTenBackPortJpaConverters.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2020 the original author or authors.
+ * Copyright 2008-2021 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.

src/main/java/org/springframework/data/jpa/domain/AbstractAuditable.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2020 the original author or authors.
+ * Copyright 2008-2021 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.

src/main/java/org/springframework/data/jpa/domain/AbstractPersistable.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2020 the original author or authors.
+ * Copyright 2013-2021 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.

src/main/java/org/springframework/data/jpa/domain/JpaSort.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2020 the original author or authors.
+ * Copyright 2008-2021 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.

src/main/java/org/springframework/data/jpa/domain/Specification.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2018-2020 the original author or authors.
+ * Copyright 2018-2021 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.

src/main/java/org/springframework/data/jpa/domain/SpecificationComposition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2020 the original author or authors.
+ * Copyright 2008-2021 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.