[php-src] Issue #8832: Support "protocol_version" stream context option for proxy connections

Issue: https://github.com/php/php-src/issues/8832 Author: onyn ### Description Hello. We have [protocol_version](https://www.php.net/manual/en/context.http.php#context.http.protocol-version) option for talking with remote host using specified HTTP protocol version. However, HTTP connection to proxy always goes with HTTP/1.0 which upsets my proxy server. Example: ```php <?php $ctx = stream_context_create( ['http' => ['proxy' => 'tcp://corporate-proxy.example:3128']] ); echo file_get_contents("https://getcomposer.org/versions", false, $ctx); ``` Result: ``` Warning: file_get_contents(): SSL: Connection reset by peer in a.php on line 5 Warning: file_get_contents(https://getcomposer.org/versions): Failed to open stream: Cannot connect to HTTPS server through proxy in a.php on line 5 ``` Actual request as seen by wireshark: ``` CONNECT getcomposer.org:443 HTTP/1.0 HTTP/1.1 426 Upgrade Required date: Mon, 20 Jun 2022 10:23:30 GMT server: envoy connection: close content-length: 0 ``` My proxy server supports only HTTP/1.1. So it's would be very handy to have an option for configuring http protocol version for proxy connections.