Update dependabot.yml

Stop putting PR's in for major dependency updates

.github/dependabot.yml

@@ -7,5 +7,9 @@ version: 2
 updates:
   - package-ecosystem: "npm" # See documentation for possible values
     directory: "/" # Location of package manifests
+    open-pull-requests-limit: 5
+    ignore:
+      - dependency-name: "*"
+        update-types: ["version-update:semver-major"]
     schedule:
       interval: "weekly"