ext/curl: Add HTTP/3 constants (#15350)

This intends to supersede the two following PRs:
 - #12000 because it does not modify the stub file, but only update the
   arginfo file. It also proposes to merge to GA branches, and is
   currently marked as Requires RM Approval.
 - #12543 Essentially the same as this PR and from the same author, as
   this, but its about a year old and requires rebasing anyway.

This adds the `CURL_HTTP_VERSION_3` and `CURL_HTTP_VERSION_3ONLY`
constants on relevant versions (7.66 and 7.88 respectively).

It is possible to use HTTP/3 without having these constants declared,
but having them declared in PHP makes things more approachable and
"official".

NEWS

@@ -12,6 +12,10 @@ PHP                                                                        NEWS
   . Passing E_USER_ERROR to trigger_error() is now deprecated. (Girgias)
   . Fixed bug GH-15292 (Dynamic AVX detection is broken for MSVC). (nielsdos)
 
+- Curl:
+  . Added constants CURL_HTTP_VERSION_3 (libcurl 7.66) and CURL_HTTP_VERSION_3ONLY
+    (libcurl 7.88) as options for CURLOPT_HTTP_VERSION (Ayesh Karunaratne)
+
 - Date:
   . Constants SUNFUNCS_RET_TIMESTAMP, SUNFUNCS_RET_STRING, and SUNFUNCS_RET_DOUBLE
     are now deprecated. (Jorg Sowa)

UPGRADING

@@ -244,6 +244,8 @@ PHP 8.4 UPGRADE NOTES
   . curl_version() returns an additional feature_list value, which is an
     associative array of all known Curl features, and whether they are
     supported (true) or not (false).
+  . Added CURL_HTTP_VERSION_3 and CURL_HTTP_VERSION_3ONLY constants (available
+    since libcurl 7.66 and 7.88) as available options for CURLOPT_HTTP_VERSION.
 
 - Date:
   . Added static methods
@@ -881,6 +883,10 @@ PHP 8.4 UPGRADE NOTES
   . PHP_OUTPUT_HANDLER_PROCESSED.
   . PHP_SBINDIR.
 
+- Curl:
+  . CURL_HTTP_VERSION_3.
+  . CURL_HTTP_VERSION_3ONLY.
+
 - Intl:
   . The IntlDateFormatter class exposes now the new PATTERN constant
     reflecting udat api's UDAT_PATTERN.

ext/curl/curl.stub.php

@@ -3102,6 +3102,11 @@
  * @cvalue CURLINFO_RETRY_AFTER
  */
 const CURLINFO_RETRY_AFTER = UNKNOWN;
+/**
+ * @var int
+ * @cvalue CURL_HTTP_VERSION_3
+ */
+const CURL_HTTP_VERSION_3  = UNKNOWN;
 #endif
 
 #if LIBCURL_VERSION_NUM >= 0x074300 /* Available since 7.67.0 */
@@ -3547,6 +3552,14 @@
 const CURLOPT_QUICK_EXIT = UNKNOWN;
 #endif
 
+#if LIBCURL_VERSION_NUM >= 0x075800 /* Available since 7.88.0 */
+/**
+ * @var int
+ * @cvalue CURL_HTTP_VERSION_3ONLY
+ */
+const CURL_HTTP_VERSION_3ONLY  = UNKNOWN;
+#endif
+
 /**
  * @var int
  * @cvalue CURLOPT_SAFE_UPLOAD