Merge pull request #3835 from DSpace/dependabot/npm_and_yarn/isbot-5.1.21

Bump isbot from 5.1.17 to 5.1.21

Author: tdonohue

package-lock.json

@@ -137,7 +137,7 @@
     "filesize": "^6.1.0",
     "http-proxy-middleware": "^2.0.7",
     "http-terminator": "^3.2.0",
-    "isbot": "^5.1.17",
+    "isbot": "^5.1.21",
     "js-cookie": "2.2.1",
     "js-yaml": "^4.1.0",
     "json5": "^2.2.3",