refactor(docs): index: rename version badge to show 'maven' as label

docs/index.md

-[![latest version][badge-latest-tag]][project-packages]
+[![maven][badge-latest-tag]][project-packages]
 [![pipeline state][badge-master-pipe]][project-pipelines]
 [![latest dev pipeline][badge-latest-pipe]][project-pipelines]
 [![License GPLv3][badge-gplv3]][gplv3]
@@ -27,7 +27,7 @@ The source code is publicly available from the [transfer portal][transferportal]
 [badge-conventional-commits]: https://img.shields.io/badge/Conventional%20Commits-1.0.0-orange.svg
 [badge-gplv3]: https://img.shields.io/badge/License-GPLv3-blue.svg
 [badge-latest-pipe]: https://img.shields.io/badge/dynamic/json?color=lightgrey&label=latest%20dev%20pipeline&query=%24%5B0%5D.status&url=https%3A%2F%2Ftransfer.hft-stuttgart.de%2Fgitlab%2Fapi%2Fv4%2F%2Fprojects%2F154%2Fpipelines%3Fper_page%3D1
-[badge-latest-tag]: https://img.shields.io/badge/dynamic/json?color=green&label=latest%20release&query=%24%5B0%5D.name&url=https%3A%2F%2Ftransfer.hft-stuttgart.de%2Fgitlab%2Fapi%2Fv4%2Fprojects%2F154%2Frepository%2Ftags%3Fper_page%3D1
+[badge-latest-tag]: https://img.shields.io/badge/dynamic/json?color=green&label=maven&query=%24%5B0%5D.name&url=https%3A%2F%2Ftransfer.hft-stuttgart.de%2Fgitlab%2Fapi%2Fv4%2Fprojects%2F154%2Frepository%2Ftags%3Fper_page%3D1
 [badge-master-pipe]: https://transfer.hft-stuttgart.de/gitlab/9Lukas5/unified-ticketing/badges/master/pipeline.svg
 [convcomm]: https://conventionalcommits.org
 [gplv3]: unified-ticketing/license-softlink.md