fix: upgrade classnames from 2.4.0 to 2.5.1

Snyk has created this PR to upgrade classnames from 2.4.0 to 2.5.1.

See this package in npm:
https://www.npmjs.com/package/classnames

See this project in Snyk:
https://app.snyk.io/org/mastermindzh/project/6eb54845-2bb5-45e0-80e2-6b3a1c53eee6?utm_source=github&utm_medium=referral&page=upgrade-pr

package.json

@@ -52,7 +52,7 @@
     "@fortawesome/fontawesome-svg-core": "^6.4.2",
     "@fortawesome/free-solid-svg-icons": "^6.4.2",
     "@fortawesome/react-fontawesome": "^0.2.0",
-    "classnames": "^2.4.0",
+    "classnames": "^2.5.1",
     "disqus-react": "^1.1.5",
     "gatsby": "^5.13.2",
     "gatsby-link": "^5.12.1",