Bump follow-redirects in /platypush/backend/http/webapp

Bumps [follow-redirects](https://github.com/follow-redirects/follow-redirects) from 1.15.4 to 1.15.6.
- [Release notes](https://github.com/follow-redirects/follow-redirects/releases)
- [Commits](https://github.com/follow-redirects/follow-redirects/compare/v1.15.4...v1.15.6)

---
updated-dependencies:
- dependency-name: follow-redirects
  dependency-type: indirect
...

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

platypush/backend/http/webapp/package-lock.json

@@ -6533,9 +6533,9 @@
       "dev": true
     },
     "node_modules/follow-redirects": {
-      "version": "1.15.4",
-      "resolved": "https://registry.npmjs.org/follow-redirects/-/follow-redirects-1.15.4.tgz",
-      "integrity": "sha512-Cr4D/5wlrb0z9dgERpUL3LrmPKVDsETIJhaCMeDfuFYcqa5bldGV6wBsAN6X/vxlXQtFBMrXdXxdL8CbDTGniw==",
+      "version": "1.15.6",
+      "resolved": "https://registry.npmjs.org/follow-redirects/-/follow-redirects-1.15.6.tgz",
+      "integrity": "sha512-wWN62YITEaOpSK584EZXJafH1AGpO8RVgElfkuXbTOrPX4fIfOyEpW/CsiNd8JdYrAoOvafRTOEnvsO++qCqFA==",
       "funding": [
         {
           "type": "individual",