fix: upgrade i18n from 0.11.1 to 0.15.1

Snyk has created this PR to upgrade i18n from 0.11.1 to 0.15.1.

See this package in npm:
i18n

See this project in Snyk:
https://app.snyk.io/org/security-k49/project/7b60bbc2-1b92-4e8d-89fb-f2e91165613d?utm_source=github-enterprise&utm_medium=referral&page=upgrade-pr

package.json

@@ -150,7 +150,7 @@
     "hbs": "^4.0.4",
     "helmet": "^4.0.0",
     "html-entities": "^1.3.1",
-    "i18n": "^0.11.1",
+    "i18n": "^0.15.1",
     "js-yaml": "^3.14.0",
     "jsonwebtoken": "0.4.0",
     "jssha": "^3.1.1",