Update PasswordEncoder declaration

Closes gh-10910

Author: talerngpong

docs/modules/ROOT/pages/features/integrations/cryptography.adoc

@@ -202,10 +202,13 @@ The password package of the `spring-security-crypto` module provides support for
 [source,java]
 ----
 public interface PasswordEncoder {
+	String encode(CharSequence rawPassword);
 
-String encode(String rawPassword);
+	boolean matches(CharSequence rawPassword, String encodedPassword);
 
-boolean matches(String rawPassword, String encodedPassword);
+	default boolean upgradeEncoding(String encodedPassword) {
+		return false;
+	}
 }
 ----
 ====