TASK: Rename method

* To follow CGL

Relates: #33

src/Standards/Typo3Update/Sniffs/LegacyClassnames/ClassnameCheckerTrait.php

@@ -62,7 +62,7 @@ trait ClassnameCheckerTrait
      *
      * @return bool
      */
-    protected function findPrev()
+    protected function shouldLookBefore()
     {
         return false;
     }

src/Standards/Typo3Update/Sniffs/LegacyClassnames/StaticCallSniff.php

@@ -32,7 +32,7 @@ class Typo3Update_Sniffs_LegacyClassnames_StaticCallSniff implements PHP_CodeSni
      *
      * @return bool
      */
-    protected function findPrev()
+    protected function shouldLookBefore()
     {
         return true;
     }