[docs] update build frequency to daily (#8781)

We're doing it daily now. 🎉 

---

- [x] I’ve reviewed the contributor guide and applied the relevant
portions to this PR.

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

- See our [contributor
guide]([https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md](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.
- Dart contributions to our repos should follow the [Dart style
guide](https://dart.dev/guides/language/effective-dart) and use `dart
format`.
- Java and Kotlin contributions should strive to follow Java and Kotlin
best practices
([discussion](#8098)).
</details>

Author: pq

kokoro/README.md

@@ -4,12 +4,9 @@ This is the configuration for the `flutter-intellij-kokoro` job. Currently, the
 `gcp_windows` config is ignored; when this project was under active development
 the Windows support was not adequate. The `macos_external` config is used
 to do CI activities. It runs unit tests on presubmit and commit, checks the code
-for compilation problems in all supported IDEs, and performs a weekly dev-channel
+for compilation problems in all supported IDEs, and performs a daily dev-channel
 build (fully automated).
 
 Kokoro jobs run on the internal Google infrastructure. See
 https://developers.google.com/marketing/engineering/tools/kokoro
 for more about it. It has no special permissions.
-
-It is maintained by the Dart DevTools team. Currently, the primary contacts
-are stevemessick and helin24 (GitHub ids).