Upgrade to GitHub-native Dependabot (#4984)

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

.github/dependabot.yml

@@ -0,0 +1,27 @@
+version: 2
+updates:
+- package-ecosystem: nuget
+  directory: "/"
+  schedule:
+    interval: daily
+  open-pull-requests-limit: 10
+  ignore:
+  - dependency-name: NUnit
+    versions:
+    - 3.13.0
+    - 3.13.1
+  - dependency-name: Google.Protobuf
+    versions:
+    - 3.15.0
+    - 3.15.1
+    - 3.15.4
+  - dependency-name: FsCheck.Xunit
+    versions:
+    - 2.14.5
+    - 2.15.0
+  - dependency-name: FsCheck
+    versions:
+    - 2.14.5
+  - dependency-name: FluentAssertions
+    versions:
+    - 5.9.0