Replaced master branch with main in readmes

DEVELOPMENT.md

@@ -9,9 +9,9 @@ Please also read the [CONTRIBUTING.md](CONTRIBUTING.md).
  * PHP Composer (Development/Building only)
 
 ## Local build
-The following instructions explain how to get, build and run the latest Engelsystem version directly from the git master branch (may be unstable!).
+The following instructions explain how to get, build and run the latest Engelsystem version directly from the git main branch (may be unstable!).
 
-* Clone the master branch: `git clone https://github.com/engelsystem/engelsystem.git`
+* Clone the main branch: `git clone https://github.com/engelsystem/engelsystem.git`
 * Install [Composer](https://getcomposer.org/download/) and [Yarn](https://yarnpkg.com/en/docs/install) (which requires [Node.js](https://nodejs.org/en/download/package-manager/))
 * Install project dependencies:
   ```bash

README.md

@@ -1,5 +1,5 @@
-[![pipeline status](https://chaos.expert/engelsystem/engelsystem/badges/master/pipeline.svg)](https://chaos.expert/engelsystem/engelsystem/commits/master)
-[![coverage report](https://chaos.expert/engelsystem/engelsystem/badges/master/coverage.svg)](https://chaos.expert/engelsystem/engelsystem/commits/master)
+[![pipeline status](https://chaos.expert/engelsystem/engelsystem/badges/main/pipeline.svg)](https://chaos.expert/engelsystem/engelsystem/commits/main)
+[![coverage report](https://chaos.expert/engelsystem/engelsystem/badges/main/coverage.svg)](https://chaos.expert/engelsystem/engelsystem/commits/main)
 [![Codacy Badge](https://api.codacy.com/project/badge/Grade/20b3b0b4e93344a29da6bec77f329e7a)](https://www.codacy.com/app/engelsystem/engelsystem)
 [![GPL](https://img.shields.io/github/license/engelsystem/engelsystem.svg?maxAge=2592000)](LICENSE)