Fix undefined property $handle

Author: sandrokeil

CHANGELOG.md

@@ -10,6 +10,18 @@
 
 ### Fixed
 
+## 0.3.1 (2020-07-14)
+
+### Added
+
+### Deprecated
+
+### Removed
+
+### Fixed
+
+* Undefined property `$handle` in `\ArangoDb\Http\Client`
+
 ## 0.3.0 (2020-07-07)
 
 ### Added

src/Http/Client.php

@@ -359,6 +359,6 @@ private function open(RequestInterface $request): void
     private function close(): void
     {
         fclose($this->handle);
-        unset($this->handle);
+        $this->handle = null; // @phpstan-ignore-line
     }
 }