Bump helmet from 7.0.0 to 7.1.0 in /backend

Bumps [helmet](https://github.com/helmetjs/helmet) from 7.0.0 to 7.1.0.
- [Changelog](https://github.com/helmetjs/helmet/blob/main/CHANGELOG.md)
- [Commits](https://github.com/helmetjs/helmet/compare/v7.0.0...v7.1.0)

---
updated-dependencies:
- dependency-name: helmet
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

backend/package.json

@@ -53,7 +53,7 @@
     "graphql-redis-subscriptions": "^2.2.1",
     "graphql-shield": "~7.2.2",
     "graphql-tag": "~2.10.3",
-    "helmet": "~7.0.0",
+    "helmet": "~7.1.0",
     "ioredis": "^4.16.1",
     "jsonwebtoken": "~8.5.1",
     "languagedetect": "^2.0.0",

backend/yarn.lock

@@ -6304,10 +6304,10 @@ he@^1.2.0:
   resolved "https://registry.yarnpkg.com/he/-/he-1.2.0.tgz#84ae65fa7eafb165fddb61566ae14baf05664f0f"
   integrity sha512-F/1DnUGPopORZi0ni+CvrCgHQ5FyEAHRLSApuYWMmrbSwoN2Mn/7k+Gl38gJnR7yyDZk6WLXwiGod1JOWNDKGw==
 
-helmet@~7.0.0:
-  version "7.0.0"
-  resolved "https://registry.yarnpkg.com/helmet/-/helmet-7.0.0.tgz#ac3011ba82fa2467f58075afa58a49427ba6212d"
-  integrity sha512-MsIgYmdBh460ZZ8cJC81q4XJknjG567wzEmv46WOBblDb6TUd3z8/GhgmsM9pn8g2B80tAJ4m5/d3Bi1KrSUBQ==
+helmet@~7.1.0:
+  version "7.1.0"
+  resolved "https://registry.yarnpkg.com/helmet/-/helmet-7.1.0.tgz#287279e00f8a3763d5dccbaf1e5ee39b8c3784ca"
+  integrity sha512-g+HZqgfbpXdCkme/Cd/mZkV0aV3BZZZSugecH03kl38m/Kmdx8jKjBikpDj2cr+Iynv4KpYEviojNdTJActJAg==
 
 homedir-polyfill@^1.0.1:
   version "1.0.3"