chore: core-styles v2.16.3

[wesleyboar]

Overview

Fix CSS build warning about invalid syntax.

Warning

``` warnings when minifying css: ▲ [WARNING] Unexpected "not(" [css-syntax-error] :2542:15: 2542 │ fieldset:where(not(:last-child)){margin-bottom:3.5rem} ```

Related

• warning began after #270
• warning fixed in https://github.com/TACC/Core-Styles/commit/97e59a9

Changes

• installed Core-Styles v2.16.3

Testing / UI / Notes

Skipped.

The warning was very clear to me, the author of that line of CSS. The warning should not affect TUP, because TUP does not use <fieldset>'s.

[jarosenb]

Rolled into #273.