Bump rollup from 2.75.5 to 2.75.7 in /src/pretix/static/npm_dir

Bumps [rollup](https://github.com/rollup/rollup) from 2.75.5 to 2.75.7.
- [Release notes](https://github.com/rollup/rollup/releases)
- [Changelog](https://github.com/rollup/rollup/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rollup/rollup/compare/v2.75.5...v2.75.7)

---
updated-dependencies:
- dependency-name: rollup
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

src/pretix/static/npm_dir/package-lock.json

@@ -3909,9 +3909,9 @@
       }
     },
     "rollup": {
-      "version": "2.75.5",
-      "resolved": "https://registry.npmjs.org/rollup/-/rollup-2.75.5.tgz",
-      "integrity": "sha512-JzNlJZDison3o2mOxVmb44Oz7t74EfSd1SQrplQk0wSaXV7uLQXtVdHbxlcT3w+8tZ1TL4r/eLfc7nAbz38BBA==",
+      "version": "2.75.7",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-2.75.7.tgz",
+      "integrity": "sha512-VSE1iy0eaAYNCxEXaleThdFXqZJ42qDBatAwrfnPlENEZ8erQ+0LYX4JXOLPceWfZpV1VtZwZ3dFCuOZiSyFtQ==",
       "requires": {
         "fsevents": "~2.3.2"
       }