Cleanup middleware logic

* Http2Connection now sets up the streams and returns a responseStream

tests/Connection/Http2ConnectionTest.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace NoccyLabs\React\Http2\Connection;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+
+#[CoversClass(Http2Connection::class)]
+class Http2ConnectionTest extends \PHPUnit\Framework\TestCase
+{
+
+}

tests/Http2MiddlewareTest.php

@@ -14,17 +14,30 @@ class Http2MiddlewareTest extends \PHPUnit\Framework\TestCase
 
     public function testInvalidUpgradeRequests()
     {
+        $middleware = new Http2Middleware();
+
         $request = new ServerRequest("GET", "/", [
             "Upgrade" => "h2",
             "x-forwarded-proto" => "http"
         ]);
 
-        $middleware = new Http2Middleware();
+        /** @var ResponseInterface $response */
+        $response = $middleware($request);
+
+        $this->assertEquals(Response::STATUS_BAD_REQUEST, $response->getStatusCode());
+        $this->assertEquals("Unsupported protocol", $response->getBody());
+
+        $request = new ServerRequest("GET", "/", [
+            "Upgrade" => "h2c",
+            "x-forwarded-proto" => "http",
+        ]);
 
         /** @var ResponseInterface $response */
         $response = $middleware($request);
 
         $this->assertEquals(Response::STATUS_BAD_REQUEST, $response->getStatusCode());
+        $this->assertEquals("Unsupported protocol", $response->getBody());
+
     }
 
     public function testHandlingUpgradeRequest()