Bump on-headers and @sap/approuter in /app

Bumps [on-headers](https://github.com/jshttp/on-headers) to 1.1.0 and updates ancestor dependency @sap/approuter. These dependencies need to be updated together.


Updates `on-headers` from 1.0.2 to 1.1.0
- [Release notes](https://github.com/jshttp/on-headers/releases)
- [Changelog](https://github.com/jshttp/on-headers/blob/master/HISTORY.md)
- [Commits](jshttp/on-headers@v1.0.2...v1.1.0)

Updates `@sap/approuter` from 20.7.0 to 20.7.1

---
updated-dependencies:
- dependency-name: on-headers
  dependency-version: 1.1.0
  dependency-type: indirect
- dependency-name: "@sap/approuter"
  dependency-version: 20.7.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]