Issue #2563799 by dawehner: Upgrade Guzzle to a tagged release

core/composer.json

core/composer.lock

core/vendor/composer/installed.json

core/vendor/guzzlehttp/guzzle/CHANGELOG.md

core/vendor/guzzlehttp/guzzle/README.md

core/vendor/guzzlehttp/guzzle/UPGRADING.md

core/vendor/guzzlehttp/guzzle/composer.json

core/vendor/guzzlehttp/guzzle/src/Client.php

core/vendor/guzzlehttp/guzzle/src/ClientInterface.php

core/vendor/guzzlehttp/guzzle/src/Cookie/CookieJar.php

core/vendor/guzzlehttp/guzzle/src/Cookie/FileCookieJar.php

.../vendor/guzzlehttp/guzzle/src/Cookie/SessionCookieJar.php

core/vendor/guzzlehttp/guzzle/src/Cookie/SetCookie.php

core/vendor/guzzlehttp/guzzle/src/Handler/CurlFactory.php

core/vendor/guzzlehttp/guzzle/src/Handler/EasyHandle.php

core/vendor/guzzlehttp/guzzle/src/Handler/MockHandler.php

core/vendor/guzzlehttp/guzzle/src/Handler/StreamHandler.php

core/vendor/guzzlehttp/guzzle/src/RedirectMiddleware.php

core/vendor/guzzlehttp/guzzle/src/RequestOptions.php

core/vendor/guzzlehttp/guzzle/src/TransferStats.php