fix: upgrade @primer/css from 21.3.1 to 21.3.6

Snyk has created this PR to upgrade @primer/css from 21.3.1 to 21.3.6.

See this package in npm:
@primer/css

See this project in Snyk:
https://app.snyk.io/org/kaliforniashell-Ae5sYsNoyPTmeK9zLiMZTf/project/80bc1c32-9f0b-4440-ac09-db56f0912ce1?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot

package-lock.json

@@ -231,7 +231,7 @@
     "@octokit/plugin-retry": "7.1.2",
     "@octokit/request-error": "6.1.1",
     "@primer/behaviors": "^1.7.0",
-    "@primer/css": "^21.3.1",
+    "@primer/css": "^21.3.6",
     "@primer/live-region-element": "^0.7.0",
     "@primer/octicons": "^19.11.0",
     "@primer/octicons-react": "^19.11.0",