Cannot upgrade GuzzleHttp to 6.5.0

[ghnp5]

• [x] I have read the README entirely
• [x] I have verified in the issues that my problem hasn't already been resolved

Setup

• Operating System: Linux
• PHP Version: 7.3
• web-push-php Version: 5.2.4 latest

Problem

When upgrading to GuzzleHttp 6.5.0, the following error happens:

Uncaught Error [0]: Call to undefined method Error::getRequest() #at /opt/app/vendor/Minishlink/WebPush/WebPush.php(180) #0 /opt/app/vendor/GuzzleHttp/Promise/Promise.php(203): Minishlink\WebPush\WebPush->Minishlink\WebPush{closure}(Object(Error)) #1 /opt/app/vendor/GuzzleHttp/Promise/Promise.php(156): GuzzleHttp\Promise\Promise::callHandler(2, Object(Error), Array) #2 /opt/app/vendor/GuzzleHttp/Promise/TaskQueue.php(47): GuzzleHttp\Promise\Promise::GuzzleHttp\Promise{closure}() #3 /opt/app/vendor/GuzzleHttp/Handler/CurlMultiHandler.php(118): GuzzleHttp\Promise\TaskQueue->run() #4 /opt/app/vendor/GuzzleHttp/Handler/CurlMultiHandler.php(145): GuzzleHttp\Handler\CurlMultiHandler->tick() #5 /opt/app/vendor/GuzzleHttp/Promise/Promise.php(246): GuzzleHttp\Handler\CurlMultiHandler->execute(true) #6 /opt/app/vendor/GuzzleHttp/Promise/Promise.php(223): GuzzleHttp\Promise\Promise->invokeWaitFn() #7 /opt/app/vendor/GuzzleHttp/Promise/Promise.php(267): GuzzleHttp\Promise\Promise->waitIfPending() #8 /opt/app/vendor/GuzzleHttp/Promise/Promise.php(225): GuzzleHttp\Promise\Promise->invokeWaitList() #9 /opt/app/vendor/GuzzleHttp/Promise/Promise.php(62): GuzzleHttp\Promise\Promise->waitIfPending() #10 /opt/app/vendor/Minishlink/WebPush/WebPush.php(185): GuzzleHttp\Promise\Promise->wait() #11 Minishlink\WebPush\WebPush->flush()

Features Used

• [x] VAPID Support
• [ ] GCM API Key
• [x] Sending with Payload