Rename method for v3.

module/VuFind/src/VuFind/Config/PluginManager.php

@@ -53,7 +53,7 @@ class PluginManager extends Base
      *
      * @SuppressWarnings(PHPMD.UnusedFormalParameter)
      */
-    public function validatePlugin($plugin)
+    public function validate($plugin)
     {
         // Assume everything is okay.
     }

module/VuFind/src/VuFind/ServiceManager/AbstractPluginManager.php

@@ -72,7 +72,7 @@ abstract class AbstractPluginManager extends Base
      * @throws ServiceManagerRuntimeException if invalid
      * @return void
      */
-    public function validatePlugin($plugin)
+    public function validate($plugin)
     {
         $expectedInterface = $this->getExpectedInterface();
         if (!($plugin instanceof $expectedInterface)) {