build: add waterdog-snapshots repo to platform-inject-runtime (#1816)

### Motivation
The build currently fails due to a missing dependency for Yamler-Core
which is provided by the waterdog snapshots repository. This repository
is currently not added to the platform-inject-runtime module, causing
the build to fail.

### Modification
Add the waterdog snapshots repo to the platform-inject-runtime module.

### Result
The build succeeds again.

Author: derklaro

ext/platform-inject-support/runtime/build.gradle.kts

@@ -23,6 +23,7 @@ plugins {
 
 repositories {
   maven("https://repo.waterdog.dev/releases/")
+  maven("https://repo.waterdog.dev/snapshots/")
   maven("https://repo.loohpjames.com/repository")
   maven("https://repo.md-5.net/repository/releases/")
   maven("https://repo.md-5.net/repository/snapshots/")