Update dependency @tryghost/string to v0.2.21

Author: renovate[bot]

packages/security/package.json

@@ -32,7 +32,7 @@
     "uuid": "9.0.1"
   },
   "dependencies": {
-    "@tryghost/string": "0.2.15",
+    "@tryghost/string": "0.2.21",
     "bcryptjs": "2.4.3"
   }
 }

yarn.lock

@@ -2625,10 +2625,10 @@
     "@tryghost/nql-lang" "^0.6.2"
     mingo "^2.2.2"
 
-"@tryghost/[email protected].15":
-  version "0.2.15"
-  resolved "https://registry.yarnpkg.com/@tryghost/string/-/string-0.2.15.tgz#5cbe2cd9b6eacfe5a3ab867ff82ecbdb030e803e"
-  integrity sha512-SEWkwpKV/bkszbnYWlfeFlHR/E91AW81HGmpMJG6oP+FLy8m+JPbXCBlYyGO60R4gRa5JawnIY5NORYjfzWLBQ==
+"@tryghost/[email protected].21":
+  version "0.2.21"
+  resolved "https://registry.yarnpkg.com/@tryghost/string/-/string-0.2.21.tgz#7294e3fb9dad595b6e180f8bbe75c33845dc45de"
+  integrity sha512-ILG3h+I432rlgD46tHrugkxEnJ8mh73JxKco4B/uIlBDv5evZjq9psIXt595ZA0Q8DuKMQKZUeVZYV9GBLA1eQ==
   dependencies:
     unidecode "^0.1.8"