Try to get dependabot ignores correct

Author: vcsjones

.github/dependabot.yml

@@ -9,23 +9,8 @@ updates:
     directory: "/"
     schedule:
       interval: "weekly"
-    groups:
-      azure-dependencies:
-        patterns:
-          - "Azure.*"
-        update-types: ["major", "minor", "patch"]
-      dotnet-dependencies:
-        patterns:
-          - "Microsoft.Extensions.*"
-          - "System.*"
-        update-types: ["minor", "patch"]
-      test-dependencies:
-        patterns:
-          - "xunit.*"
-          - "Microsoft.NET.Test.SDK"
-          - "MinVer"
-        update-types: ["major", "minor", "patch"]
-      third-party-dependencies:
-        patterns:
-          - "XenoAtom.*"
-        update-types: ["major", "minor", "patch"]
+    ignore:
+      - dependency-name: "System.*"
+        update-types: ["version-update:semver-major"]
+      - dependency-name: "Microsoft.Extensions.*"
+        update-types: ["version-update:semver-major"]