ci: does not use yaml anchors

.github/dependabot.yaml

@@ -2,14 +2,17 @@ version: 2
 updates:
   - package-ecosystem: github-actions
     directory: /
-    schedule: &schedule
+    schedule:
       interval: weekly
       time: "07:00"
       timezone: "Asia/Tokyo"
     labels: ["kind/dependencies", "area/github_actions"]
   - package-ecosystem: cargo
     directory: /
-    schedule: *schedule
+    schedule: # github does not support yaml anchors
+      interval: weekly
+      time: "07:00"
+      timezone: "Asia/Tokyo"
     labels: ["kind/dependencies", "area/rust"]
     # https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#groups
     # If a dependency doesn't belong to any group, Dependabot will continue to raise single pull requests to update the dependency to its latest version as normal.