chore: configure Dependabot grouping for consolidated PRs

Author: rsafier

.github/dependabot.yml

@@ -5,8 +5,20 @@ updates:
     schedule:
       interval: "weekly"
     open-pull-requests-limit: 5
+    groups:
+      nuget-minor-patch:
+        update-types:
+          - "minor"
+          - "patch"
+      nuget-major:
+        update-types:
+          - "major"
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule:
       interval: "weekly"
     open-pull-requests-limit: 5
+    groups:
+      actions-all:
+        patterns:
+          - "*"