[ci skip] Update the min curl version in the sync-constants.php script

PHP 8.0 bumped the min curl version to 7.29.0

Closes GH-7805.

Author: stof

ext/curl/sync-constants.php

@@ -12,7 +12,7 @@
 
 const SOURCE_FILE = __DIR__ . '/interface.c';
 
-const MIN_SUPPORTED_CURL_VERSION = '7.15.5';
+const MIN_SUPPORTED_CURL_VERSION = '7.29.0';
 
 const IGNORED_CONSTANTS = [
     'CURLOPT_PROGRESSDATA'