Fix recommended task dependency configuration

`compileJava.dependsOn(processResources)` is not enough to ensure the
correct behavior. Using `dependsOn` only affects the execution order
(`processResources` before `compileJava`) but not the up-to-date check
of `compileJava`. After modifying
`META-INF/additional-spring-configuration-metadata.json`, the
`processResouces` task will considered out-of-date and will be
re-executed, but after that `compileJava` will still be considered
up-to-date which causes the changes not to be merged into
`META-INF/spring-configuration-metadata.json`

With this change the up-do-date check of `compileJava` is affected,
too. Therefore, it will correctly re-execute the
configuration-processor when
`META-INF/additional-spring-configuration-metadata.json` was changed.

See gh-20323

spring-boot-project/spring-boot-docs/src/main/asciidoc/appendix-configuration-metadata.adoc

@@ -730,7 +730,7 @@ If you are using an `additional-spring-configuration-metadata.json` file, the `c
 
 [source,groovy,indent=0,subs="verbatim,quotes,attributes"]
 ----
-	compileJava.dependsOn(processResources)
+	compileJava.inputs.files(processResources)
 ----
 
 This dependency ensures that the additional metadata is available when the annotation processor runs during compilation.