WEBSERVICE is HTTP client agnostic

HTTP client must be configured via `Settings::setHttpClient()`. This is
a small breaking change, but only for the very few people who started using
WEBSERVICE from last version.

Fixes #1562
Closes #1568

Author: PowerKiKi

CHANGELOG.md

@@ -13,7 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 
 ### Fixed
 
-- nothing
+- WEBSERVICE is HTTP client agnostic and must be configured via `Settings::setHttpClient()` [#1562](https://github.com/PHPOffice/PhpSpreadsheet/issues/1562)
 
 ### Changed
 

composer.json

@@ -57,7 +57,8 @@
         "markbaker/complex": "^1.4",
         "markbaker/matrix": "^1.2",
         "psr/simple-cache": "^1.0",
-        "guzzlehttp/guzzle": "^7.0"
+        "psr/http-client": "^1.0",
+        "psr/http-factory": "^1.0"
     },
     "require-dev": {
         "dompdf/dompdf": "^0.8.5",