Make dependency available for javadoc generation

See spring-projectsgh-17111

Author: dreis2211

spring-boot-project/spring-boot-docs/pom.xml

@@ -437,6 +437,11 @@
 			<artifactId>commons-dbcp2</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.apache.derby</groupId>
+			<artifactId>derby</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>org.apache.kafka</groupId>
 			<artifactId>kafka-streams</artifactId>