[ci] print tag message in `latest`

.ci/upload_win_installer.sh

@@ -5,5 +5,5 @@ tag=$(git describe --exact-match)
 [ "$tag" ] || exit
 
 curl -T 'packages\win_installer\output\Aegisub-Japan7-x64.exe' --user $FTP_USER:$FTP_PASS "$dest/Aegisub-Japan7-${tag#v}-x64.exe"
-printf "${tag#v}\n$(git tag -l --format='%contents' $tag)" > latest
+printf "${tag#v}\n$(git tag -l --format='%(contents)' $tag)" > latest
 curl -T latest --user "$FTP_USER:$FTP_PASS" "$dest/"