No, that's not a promise (sorry to get your hopes up). It's merely the latest hyperbole from the state's largest labor union.
But as you can see from page 33 of this document, legislative appropriations for public education do nothing but continue to climb. And that's just appropriated money -- it doesn't take into account all the other costs of public education.
What's happening is that school choice in Oklahoma is slowly expanding, and the union doesn't like it one bit.