Remove install guide via artifacts

README.md

@@ -2,14 +2,8 @@
 
 ## Installation
 
-### Release
-
 Go to [releases](https://github.com/echo-swent/echo/releases) and download the `app-debug.apk` asset from the latest release.
 
-### Artifact
-
-Go to the [Android APK Build](https://github.com/echo-swent/echo/actions/workflows/android.yml) workflow and download the `echo-app.apk` artifact from the latest successful run.
-
 ## Authentication
 
 If you have trouble logging in, please use the following test credentials: