Congress can change the date, the final date, for choosing the Electors by statute no amendment needed. Some states have early voting now but the final date must be uniform throughout the states. Mandating a day off on that day is not within the scope of the Constitution, in fact the Constitution does not even require of vote of the citizens to choose the Electors. If you want to change your state elections your state can do so.
On the surface, it sounds good, but in places like FL, it's totally unnecessary. I can early vote from 8-6 at locations around the county for November 6, starting today through Saturday Nov. 3. I could request an absentee ballot, with no reason necessary, for the next 2 or 3 years worth of elections, or I could vote conventionally from 7 am to 7 pm. What need do I have for a holiday? Why should my employer be punished monetarily for this? I do agree it may be different in other states, but in FL, it's absurd. If you don't vote in a FL election it's because you don't want to vote.
I've voted since 1984. I've either had a job or been in school that entire time. The only election I've missed has been a local primary--and that's because I really didn't care which candidate won. That's a pretty lame excuse.
You want to shut down the economy (nobody but healthcare and election officials allowed to vote) for two days every two years, and you think only trolls will oppose it? Love the way the young don't think of consequences.
Under current laws in the majority of states (30 of 50), an employer has to allow an employee to get off work to vote. (My state, FL, isn't one of them, but on the other hand, it is extremely easy to vote here, as I've outlined in another post.) https://www.businessinsider.com/can-i-leave-work-early-to-vote-2016-11