update UPGRADING.INTERNALS

Author: weltling

UPGRADING.INTERNALS

@@ -1,7 +1,8 @@
 PHP 7.1 INTERNALS UPGRADE NOTES
 
 1. Internal API changes
-  a.
+  a. Path related functions
+  b. php_win32_get_random_bytes()
 
 2. Build system changes
   a. Unix build system changes
@@ -19,6 +20,9 @@ PHP 7.1 INTERNALS UPGRADE NOTES
     - PHPAPI void php_clear_stat_cache(zend_bool clear_realpath_cache, const char *filename, size_t filename_len);
     - PHPAPI void php_stat(const char *filename, size_t filename_length, int type, zval *return_value);
 
+  b. php_win32_get_random_bytes()
+    The iternal randomness source on Windows switched to use CNG API.
+
 
 ========================
 2. Build system changes