chore(deps): bump katex from 0.16.11 to 0.16.21 (#1055)

Bumps [katex](https://github.com/KaTeX/KaTeX) from 0.16.11 to 0.16.21.
- [Release notes](https://github.com/KaTeX/KaTeX/releases)
- [Changelog](https://github.com/KaTeX/KaTeX/blob/main/CHANGELOG.md)
- [Commits](KaTeX/KaTeX@v0.16.11...v0.16.21)

---
updated-dependencies:
- dependency-name: katex
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package-lock.json

@@ -5,7 +5,7 @@
   "dependencies": {
     "@fortawesome/fontawesome-free": "^6.7.2",
     "highlight.js": "^11.11.1",
-    "katex": "^0.16.11",
+    "katex": "^0.16.21",
     "uikit": "^3.21.13",
     "www-covidcast": "https://github.com/cmu-delphi/www-covidcast/releases/download/v3.2.12/www-covidcast-3.2.12.tgz",
     "www-covidcast-classic": "https://github.com/cmu-delphi/www-covidcast-classic/releases/download/v2.6.7/www-covidcast-classic-2.6.7.tgz",