If you want to add this behaviour to a shorthand animation property definition, the order of sub-properties is as follows
animation-name - default none
animation-duration - default 0s
animation-timing-function - default ease
animation-delay - default 0s
animation-iteration-count - default 1
animation-direction - default normal
animation-fill-mode - you need to set this to forwards
animation-play-state - default running
Therefore in the most common case, the result will be something like this
animation: colorchange 1s ease 0s 1 normal forwards;
See the MDN documentation here