Added support for cloud synchronization of save data

Added support for cloud synchronization of save data. This will allow you to share save data on multiple PCs. An internet connection is required to synchronize the save data at the start and end of the game. If you can't connect to the internet, you can't synchronize save data, but you can play games.

By being able to synchronize save data, for example, if you were playing Little Saver on your desktop, you will be able to continue playing on your laptop when you are out and about. Also, even if your PC breaks down, save data will be less likely to be lost because it is stored in the cloud.

Since this function can be completed with the settings on the Steam side, there is no particular version upgrade for Little Saver. Now you can play as usual. You may have a momentary Steam sync dialog when launching the game.

By the way, regarding the question of what happens if there are different save data on multiple PCs before save data synchronization, Little Saver can recognize save data with the same number as separate save data. You can also choose whether to delete the one you don't need when importing or leave it as it is.