refactor(docs): index: make conventional commits badge orange

docs/index.md

 [![pipeline state](https://transfer.hft-stuttgart.de/gitlab/9Lukas5/unified-ticketing/badges/master/pipeline.svg)](https://transfer.hft-stuttgart.de/gitlab/9Lukas5/unified-ticketing/pipelines)
 [![License GPLv3](https://img.shields.io/badge/License-GPLv3-blue.svg)](https://www.gnu.org/licenses/gpl-3.0)
-[![Conventional Commits](https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg)](https://conventionalcommits.org)
+[![Conventional Commits](https://img.shields.io/badge/Conventional%20Commits-1.0.0-orange.svg)](https://conventionalcommits.org)
 
 # Unified Ticketing