build(deps-dev): bump @types/svg2png from 4.1.0 to 4.1.1 in /backend

Bumps [@types/svg2png](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/svg2png) from 4.1.0 to 4.1.1.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/svg2png)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

backend/package-lock.json

@@ -26,7 +26,7 @@
     "@types/react": "^16.9.35",
     "@types/react-dom": "^16.9.8",
     "@types/redis": "^2.8.22",
-    "@types/svg2png": "^4.1.0",
+    "@types/svg2png": "^4.1.1",
     "@types/yargs": "^15.0.5",
     "mocha": "^7.2.0",
     "power-assert": "^1.6.1",