[newlib-cygwin/cygwin-3_5-branch] Cygwin: add newgrp release notes

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=1f407990d291e9b99bd1393f772217331b97bd21

commit 1f407990d291e9b99bd1393f772217331b97bd21
Author:     Corinna Vinschen <corinna@vinschen.de>
AuthorDate: Sat Feb 24 13:12:00 2024 +0100
Commit:     Corinna Vinschen <corinna@vinschen.de>
CommitDate: Sat Feb 24 13:12:37 2024 +0100

    Cygwin: add newgrp release notes
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/release/3.5.1 | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/winsup/cygwin/release/3.5.1 b/winsup/cygwin/release/3.5.1
index efea5ae2f1cf..a7d74fa6b689 100644
--- a/winsup/cygwin/release/3.5.1
+++ b/winsup/cygwin/release/3.5.1
@@ -26,3 +26,6 @@ Fixes:
 
 - Fix two bugs in strptime, error checking of invalid numerical input and
   %p handling.
+
+- Fix newgrp(1) group handling.  Only allow groups already in the user
+  token, as Windows doesn't allow otherwise.