Fix codeql

Author: lohanidamodar

src/App.php

@@ -344,7 +344,7 @@ public static function error(): Hook
      * @param  string|null  $default
      * @return string|null
      */
-    public static function getEnv(string $key, string $default = null): ?string
+    public static function getEnv(string $key, ?string $default = null): ?string
     {
         return $_SERVER[$key] ?? $default;
     }

src/Request.php

@@ -136,7 +136,7 @@ public function getRawPayload(): string
      * @param  string|null  $default
      * @return string|null
      */
-    public function getServer(string $key, string $default = null): ?string
+    public function getServer(string $key, ?string $default = null): ?string
     {
         return $_SERVER[$key] ?? $default;
     }

src/Response.php

@@ -533,7 +533,7 @@ public function getHeaders(): array
      * @param  bool  $httponly
      * @param  string  $sameSite
      */
-    public function addCookie(string $name, string $value = null, int $expire = null, string $path = null, string $domain = null, bool $secure = null, bool $httponly = null, string $sameSite = null): static
+    public function addCookie(string $name, ?string $value = null, ?int $expire = null, ?string $path = null, ?string $domain = null, ?bool $secure = null, ?bool $httponly = null, ?string $sameSite = null): static
     {
         $name = strtolower($name);
 
@@ -665,7 +665,7 @@ protected function write(string $content): void
      * @param  string  $content
      * @return void
      */
-    protected function end(string $content = null): void
+    protected function end(?string $content = null): void
     {
         if (!is_null($content)) {
             echo $content;

tests/AppTest.php

@@ -467,7 +467,7 @@ public function providerRouteMatching(): array
     /**
      * @dataProvider providerRouteMatching
      */
-    public function testCanMatchRoute(string $method, string $path, string $url = null): void
+    public function testCanMatchRoute(string $method, string $path, ?string $url = null): void
     {
         $url ??= $path;
         $expected = null;