Fix license typo in README
Fix license typo in README

crepererum/KaTeX,twitwi/KaTeX,saschatimme/KaTeX,Khan/KaTeX,saschatimme/KaTeX,franciscop/KaTeX,mcanthony/KaTeX,saschatimme/KaTeX,kwangkim/KaTeX,Khan/KaTeX,kwangkim/katex-npm-0.7.0-pre,frankandrobot/KaTeX,franciscop/KaTeX,franciscop/KaTeX,azotova/KaTeX,gagern/KaTeX,saschatimme/KaTeX,frankandrobot/KaTeX,JetStarBlues/KaTeX,kevinbarabash/KaTeX,frankandrobot/KaTeX,crepererum/KaTeX,mcanthony/KaTeX,spicyj/KaTeX,zhanghuiguoanlige/KaTeX,azotova/KaTeX,twitwi/KaTeX,franciscop/KaTeX,JetStarBlues/KaTeX,kevinbarabash/KaTeX,kwangkim/katex-npm-0.7.0-pre,crepererum/KaTeX,xymostech/KaTeX,kwangkim/KaTeX,mcanthony/KaTeX,kwangkim/KaTeX,zhanghuiguoanlige/KaTeX,zhanghuiguoanlige/KaTeX,crepererum/KaTeX,frankandrobot/KaTeX,azotova/KaTeX,JetStarBlues/KaTeX,azotova/KaTeX,kwangkim/KaTeX,kevinbarabash/KaTeX,twitwi/KaTeX,azotova/KaTeX,saschatimme/KaTeX,JetStarBlues/KaTeX,spicyj/KaTeX,spicyj/KaTeX,zhanghuiguoanlige/KaTeX,gagern/KaTeX,kevinbarabash/KaTeX,gagern/KaTeX,JetStarBlues/KaTeX,twitwi/KaTeX,spicyj/KaTeX,gagern/KaTeX,franciscop/KaTeX,kwangkim/katex-npm-0.7.0-pre,xymostech/KaTeX,frankandrobot/KaTeX,kwangkim/KaTeX,zhanghuiguoanlige/KaTeX,xymostech/KaTeX,crepererum/KaTeX,xymostech/KaTeX,spicyj/KaTeX,mcanthony/KaTeX,mcanthony/KaTeX,kevinbarabash/KaTeX,kwangkim/katex-npm-0.7.0-pre,twitwi/KaTeX,gagern/KaTeX,Khan/KaTeX,kwangkim/katex-npm-0.7.0-pre,xymostech/KaTeX