Evolution by Friendship
That kind of evolution happens when your pokemon is feeling happy with you, they need love to this. However, it's not working on game by now, so if you check on your pokedex it will say that the pokemon evolves at level 0. To make the evolution happen you just need to level your pokemon up once. With the New Update of day/night time, evolutions under that condition are now working, so we can evolve to Umbreon now. Let's see the list: