fix: HTTP method name should be uppercase

Author: kenjis

tests/system/HTTP/CURLRequestTest.php

@@ -1129,7 +1129,7 @@ public function testMultipleHTTP100(): void
 
         $this->request->setOutput($output);
 
-        $response = $this->request->request('get', 'http://example.com');
+        $response = $this->request->request('GET', 'http://example.com');
 
         $this->assertSame($jsonBody, $response->getBody());