Add support for Java 21

Author: marchof

README.md

@@ -2,7 +2,7 @@ io.javaalmanac.javadoclink - Deep links for Javadoc
 ===================================================
 
 Small Java library to create deep links into generated Javadoc for all Java
-versions from 1.1 to 20.
+versions from 1.1 to 21.
 
 The library can create links for
 
@@ -23,7 +23,7 @@ The latest version can be obtained with the following Maven dependency:
 <dependency>
     <groupId>io.javaalmanac</groupId>
     <artifactId>javadoclink</artifactId>
-    <version>1.2.0</version>
+    <version>1.3.0</version>
 </dependency>
 ```
 

src/main/java/io/javaalmanac/javadoclink/JavaDocLinkImpl.java

@@ -83,6 +83,7 @@ final class JavaDocLinkImpl implements JavaDocLink {
 		VERSIONS.put("18", VERSIONS.get("11"));
 		VERSIONS.put("19", VERSIONS.get("11"));
 		VERSIONS.put("20", VERSIONS.get("11"));
+		VERSIONS.put("21", VERSIONS.get("11"));
 	}
 
 	private final String base;

src/test/java/io/javaalmanac/javadoclink/JavaDocLinkTest.java

@@ -124,6 +124,7 @@ private boolean hasNoElement(Document doc, String element, String attr, String v
 		JDK_API_DOC.put("18", "https://docs.oracle.com/en/java/javase/18/docs/api/");
 		JDK_API_DOC.put("19", "https://docs.oracle.com/en/java/javase/19/docs/api/");
 		JDK_API_DOC.put("20", "https://download.java.net/java/early_access/jdk20/docs/api/");
+		JDK_API_DOC.put("21", "https://download.java.net/java/early_access/jdk21/docs/api/");
 	}
 
 }