Exclude dependency updates other than direct dependencies (#14944)

.github/dependabot.yml

@@ -11,7 +11,7 @@ updates:
       interval: weekly
     open-pull-requests-limit: 99
     allow:
-      - dependency-type: all
+      - dependency-type: direct
 
   - package-ecosystem: bundler
     directory: "/"
@@ -19,4 +19,4 @@ updates:
       interval: weekly
     open-pull-requests-limit: 99
     allow:
-      - dependency-type: all
+      - dependency-type: direct