fix: upgrade @ndla/pager from 2.1.15 to 2.2.21

Snyk has created this PR to upgrade @ndla/pager from 2.1.15 to 2.2.21.

See this package in npm:


See this project in Snyk:
https://app.snyk.io/org/ndla/project/b8a75322-2232-4f8a-a63b-6ec5354c4f99?utm_source=github&utm_medium=referral&page=upgrade-pr

package.json

@@ -105,7 +105,7 @@
     "@ndla/listview": "^3.1.61",
     "@ndla/modal": "^2.2.12",
     "@ndla/notion": "^4.2.10",
-    "@ndla/pager": "^2.1.15",
+    "@ndla/pager": "^2.2.21",
     "@ndla/tabs": "^2.1.13",
     "@ndla/tracker": "^2.1.1",
     "@ndla/ui": "^35.0.10",