remove stale link (#8920)

Follow-up from: flutter/dart-intellij-third-party@dfaef98#r3132800413

---

Review the contribution guidelines below:

<details>
  <summary>Contribution guidelines:</summary><br>

- See
  our [contributor guide](../CONTRIBUTING.md) and
  the [Flutter organization contributor guide]([https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md)
  for general expectations for PRs.
- Larger or significant changes should be discussed in an issue before creating a PR.
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</details>

Author: pq

.github/dependabot.yml

@@ -1,6 +1,3 @@
-# See Dependabot documentation for all configuration options:
-# https://help.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
-
 version: 2
 updates:
   - package-ecosystem: "github-actions"