Easter is a combination of a christian religious holiday and pre-christian celebration of the return of the Sun after a long winter.
If you are a christian, your clothing shouldn’t be as important as the celebration of the return of Christ from death. I expect any clothes appropriate for church are good enough If you are there to impress your neighbors, then you probably shouldn’t bother going to church.
If you are celebrating spring and fertility then what you wear should be something that you can easily discard. Hopefully you’ll be some place warm enough for a proper pagan orgy.
Either way, what you wear isn’t as important as the meaning you attach to the holiday. For me, it is an opportunity to sleep late, so pajamas are appropriate attire, unless I get lucky on Saturday night.