Update dawidd6/action-send-mail action to v16 (#26485)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/announce-lts-rc.yml

@@ -17,7 +17,7 @@ jobs:
           discourse-author-username: jenkins-release-bot
           discourse-category: 23
       - name: Post on mailing list
-        uses: dawidd6/action-send-mail@ba302ba66e88942841281c984a6b31ca6d6289e6 # v11
+        uses: dawidd6/action-send-mail@d38f3f7cd391cdebfe0d38efc3998b935e951c4f # v16
         with:
           server_address: smtp.gmail.com
           server_port: 465