[HttpClient] Document new option auto_upgrade_http_version

Author: ajgarlag

http_client.rst

@@ -1789,6 +1789,15 @@ You can also pass a set of default options to your client thanks to the
 
     // ...
 
+.. versionadded:: 7.4
+
+    Starting in Symfony 7.4, the option `auto_upgrade_http_version` can
+    be set to false to disable automatic HTTP protocol version upgrade when
+    possible.
+
+    The automatic HTTP version upgrade is always disabled for HTTP/1.0 requests,
+    regardless of the option value.
+
 HTTPlug
 ~~~~~~~
 
@@ -1890,6 +1899,15 @@ You can also pass a set of default options to your client thanks to the
 
     // ...
 
+.. versionadded:: 7.4
+
+    Starting in Symfony 7.4, the option `auto_upgrade_http_version` can
+    be set to false to disable automatic HTTP protocol version upgrade when
+    possible.
+
+    The automatic HTTP version upgrade is always disabled for HTTP/1.0 requests,
+    regardless of the option value.
+
 Native PHP Streams
 ~~~~~~~~~~~~~~~~~~