Update dependabot.yml

Fix dependabot directory path

Author: AndreasReitberger

.github/dependabot.yml

@@ -1,7 +1,7 @@
 version: 2
 updates:
 - package-ecosystem: nuget
-  directory: "/"
+  directory: "/src"
   schedule:
     interval: daily
   open-pull-requests-limit: 25