Update BRANCHES.md so that it links to the LTS release tag on GitHub.

Signed-off-by: Aditya Deshpande <aditya.deshpande@arm.com>
diff --git a/BRANCHES.md b/BRANCHES.md
index 7fb706d..d4fa506 100644
--- a/BRANCHES.md
+++ b/BRANCHES.md
@@ -70,6 +70,7 @@
 - [master](https://github.com/Mbed-TLS/mbedtls/tree/master)
 - [`development`](https://github.com/Mbed-TLS/mbedtls/)
 - [`mbedtls-2.28`](https://github.com/Mbed-TLS/mbedtls/tree/mbedtls-2.28)
- maintained until at least the end of 2024.
+ maintained until at least the end of 2024, see
+  <https://github.com/Mbed-TLS/mbedtls/releases/tag/v2.28.2>.
 
 Users are urged to always use the latest version of a maintained branch.