contrib: correct string not formatted in gen_uprev_msg.py

BUG=none
TEST=none

Change-Id: I5c5b276cc7da41e2a4a09d312138674db86a42cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2507302
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
Tested-by: Paul2 Huang <paul2_huang@pegatron.corp-partner.google.com>
Commit-Queue: Yu-Ping Wu <yupingso@chromium.org>
diff --git a/contrib/gen_uprev_msg.py b/contrib/gen_uprev_msg.py
index 50c678e..458dd32 100755
--- a/contrib/gen_uprev_msg.py
+++ b/contrib/gen_uprev_msg.py
@@ -122,7 +122,7 @@
     # Output
     if changes:
         title = (f'chromeos-firmware-{board}: '
-                 'Uprev firmware to {changes[1]} for {board}')
+                 f'Uprev firmware to {changes[1]} for {board}')
         print(title)
         print()