Upgrade to GitHub-native Dependabot (#79)

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

.github/dependabot.yml

@@ -0,0 +1,21 @@
+version: 2
+updates:
+- package-ecosystem: nuget
+  directory: "/"
+  schedule:
+    interval: daily
+  open-pull-requests-limit: 10
+  ignore:
+  - dependency-name: xunit.runner.visualstudio
+    versions:
+    - "> 2.4.1, < 3"
+  - dependency-name: NLog.Schema
+    versions:
+    - 4.7.7
+    - 4.7.8
+    - 4.7.9
+  - dependency-name: NLog
+    versions:
+    - 4.7.7
+    - 4.7.8
+    - 4.7.9