Fix method signature issue

src/LoggerTrait.php

@@ -45,7 +45,7 @@ trait LoggerTrait {
 	/**
 	 * Set a logger to keep track of errors
 	 */
-	public function setLogger(LoggerInterface $logger): self
+	public function setLogger(LoggerInterface $logger): void
 	{
 		$this->logger = $logger;
 
@@ -54,7 +54,5 @@ trait LoggerTrait {
 		{
 			$this->driver->setLogger($logger);
 		}
-
-		return $this;
 	}
 }

tests/TellerTest.php

@@ -222,7 +222,7 @@ class TellerTest extends TestCase {
 		$this->teller->get($key);
 	}
 
-	public function keyValidationTests(): array
+	public static function keyValidationTests(): array
 	{
 		// {}()/@:\\\
 		return [