Any text-align utility class would do the trick. Bootstrap has been using .text-center
class for centering text for a long time now.
.text-center { text-align: center !important; }
Or you can create your own utilities. Some variations I've seen over the years:
.u-text-center { text-align: center !important; }
.ta-center { text-align: center !important; }
.ta\:c { text-align: center !important; }