Backport/v1.24 will not trigger any backport PR when labelled with backport/v1.25

[lunny]

When a PR have both backport/v1.24 and backport/v1.25. The PR will only be backport to v1.25 but not v1.24.

i.e.
go-gitea/gitea#35591
go-gitea/gitea#35584
go-gitea/gitea#35560

[yardenshoham]

Because there is no 1.24.x milestone

[lunny]

I created a new milestone for 1.24. Can the bot be triggered manually? https://github.com/go-gitea/gitea/milestone/187

[yardenshoham]

It will run on the next merge to master