Bump paperless-ngx/paperless-ngx in /projects/paperless

Bumps [paperless-ngx/paperless-ngx](https://github.com/paperless-ngx/paperless-ngx) from 2.20.10 to 2.20.15.
- [Release notes](https://github.com/paperless-ngx/paperless-ngx/releases)
- [Changelog](https://github.com/paperless-ngx/paperless-ngx/blob/dev/docs/changelog.md)
- [Commits](https://github.com/paperless-ngx/paperless-ngx/compare/v2.20.10...v2.20.15)

---
updated-dependencies:
- dependency-name: paperless-ngx/paperless-ngx
  dependency-version: 2.20.15
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

projects/paperless/docker-compose.yml

@@ -1,7 +1,7 @@
 version: '3.8'
 services:
   paperless:
-    image: ghcr.io/paperless-ngx/paperless-ngx:2.20.10
+    image: ghcr.io/paperless-ngx/paperless-ngx:2.20.15
     container_name: paperless
     restart: unless-stopped
     labels: