Depends where it rubs and how much, but you can try rotating the FD slightly, or bending the inner plate slightly (if you're sure you're on the limits)
Minor FD rub in 1st gear can be considered a feature in the absence of a gear display; stops you imagining you have a lower gear than first and experiencing the misery of trying to shift to it...
Anyone on SRAM mechanical knows how much that can suck: forgot you were in first? Here, have second!
Depends where it rubs and how much, but you can try rotating the FD slightly, or bending the inner plate slightly (if you're sure you're on the limits)