Add Dependabot configuration for dotnet-sdk

This commit introduces a new configuration for dotnet-sdk in the Dependabot file. The change includes setting the update interval to daily and adding a commit message prefix "(deps)" for the dotnet-sdk ecosystem. This ensures dependencies are regularly checked and updated, thus maintaining the project's security and functionality.

.github/dependabot.yml

@@ -1,5 +1,13 @@
 version: 2
 updates:
+- package-ecosystem: dotnet-sdk
+  labels:
+      - "dependencies"
+  commit-message:
+      prefix: "(deps)"
+  directory: "/build"
+  schedule:
+      interval: daily
 - package-ecosystem: nuget
   labels:
     - "dependencies"