Tailwind: [WARNING] "zindex" is not a known CSS property [unsupported-css-property]

[tkgdbowen]

The tailwind integration throws a warning when built in my app due to mistyped property zindex which should be z-index

react-widgets/packages/tailwind/src/multiselect.ts

Line 92 in 00b7905

zindex: 1;

[jquense]

PRs welcome!