Add an item to the NEWS.md

Author: larskanis

NEWS.md

@@ -67,6 +67,11 @@ The following bundled gems are updated.
 
 ## Compatibility issues
 
+* On Windows `$PROGRAM_NAME`, `$LOAD_PATH` and command line options `-e <script>`, `-I <path>`
+  are now encoded as UTF-8 instead of the active code page.
+  `STDIN` from pipe is also interpret as UTF-8.
+    [[Feature #20699]], [[Bug #20774]]
+
 ## Stdlib compatibility issues
 
 ## C API updates