Bump isbot from 5.1.19 to 5.1.21

Bumps [isbot](https://github.com/omrilotan/isbot) from 5.1.19 to 5.1.21.
- [Changelog](https://github.com/omrilotan/isbot/blob/main/CHANGELOG.md)
- [Commits](omrilotan/isbot@v5.1.19...v5.1.21)

---
updated-dependencies:
- dependency-name: isbot
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -39,7 +39,7 @@
     "bootstrap": "5.2.3",
     "bottlejs": "^2.0.1",
     "express": "^4.21.2",
-    "isbot": "^5.1.19",
+    "isbot": "^5.1.21",
     "pg": "^8.13.1",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",