[doc] Update release note for R-universe. (#11369)

Author: trivialfis

doc/R-package/index.rst

@@ -17,9 +17,9 @@ You have found the XGBoost R Package!
 Get Started
 ***********
 
-Since XGBoost 3.0.0, the latest R package is available on
-`https://dmlc.r-universe.dev/builds <R-universe>`__ while the one on CRAN is kept at an
-older version. We will work on helping the CRAN version to catch up in the future. In the
+Since XGBoost 3.0.0, the latest R package is available on `R-universe
+<https://dmlc.r-universe.dev/xgboost>`__ while the one on CRAN is kept at an older
+version. We will work on helping the CRAN version to catch up in the future. In the
 meantime, please use R-universe packages.
 
 * Check out the :doc:`Installation Guide </install>` for instructions on how to install

doc/changes/v3.0.0.rst

@@ -292,11 +292,15 @@ R Package
 *********
 
 We have been reworking the R package for a few releases now. In 3.0, we will start
-publishing a new R package on public repositories, likely R-universe, before moving toward
-a CRAN update. The new package features a much more ergonomic interface, which is also
-more idiomatic to R speakers. In addition, a range of new features are introduced to the
-package. To name a few, the new package includes categorical feature support,
-``QuantileDMatrix``, and an initial implementation of the external memory training.
+publishing a new R package on R-universe, before moving toward a CRAN update. The new
+package features a much more ergonomic interface, which is also more idiomatic to R
+speakers. In addition, a range of new features are introduced to the package. To name a
+few, the new package includes categorical feature support, ``QuantileDMatrix``, and an
+initial implementation of the external memory training. To test the new package:
+
+.. code-block:: R
+
+  install.packages('xgboost', repos = c('https://dmlc.r-universe.dev', 'https://cloud.r-project.org'))
 
 Also, we finally have an online documentation site for the R package featuring both
 vignettes and API references (:pr:`11166`, :pr:`11257`). A good starting point for the new interface

doc/contrib/release.rst

@@ -21,17 +21,25 @@ Making a Release
 3. Commit the change, create a PR on GitHub on release branch.  Port the bumped version to default branch, optionally with the postfix ``SNAPSHOT``.
 4. Create a tag on release branch, either on GitHub or locally.
 5. Make a release on GitHub tag page, which might be done with previous step if the tag is created on GitHub.
-6. Submit pip, CRAN, and Maven packages.
+6. Submit pip, R-universe, CRAN, and Maven packages.
 
    There are helper scripts for automating the process in ``xgboost/dev/``.
 
    + The pip package is maintained by `Hyunsu Cho <https://github.com/hcho3>`__ and `Jiaming Yuan <https://github.com/trivialfis>`__.
 
-   + The CRAN package is maintained by `Tong He <https://github.com/hetong007>`_ and `Jiaming Yuan <https://github.com/trivialfis>`__.
+   + The CRAN package and the R-universe packages are maintained by `Jiaming Yuan <https://github.com/trivialfis>`__.
 
    + The Maven package is maintained by `Nan Zhu <https://github.com/CodingCat>`_ and `Hyunsu Cho <https://github.com/hcho3>`_.
 
 
+R Universe Packages
+-------------------
+
+Since XGBoost 3.0.0, we host the R package on `R-Universe
+<https://dmlc.r-universe.dev/xgboost>`__. To make a new release, change the
+``packages.json`` in `dmlc.r-universe.dev <https://github.com/dmlc/dmlc.r-universe.dev>`__
+with a new release branch.
+
 R CRAN Package
 --------------
 Before submitting a release, one should test the package on `R-hub <https://builder.r-hub.io/>`__ and `win-builder <https://win-builder.r-project.org/>`__ first.  Please note that the R-hub Windows instance doesn't have the exact same environment as the one hosted on win-builder.
@@ -42,7 +50,17 @@ According to the `CRAN policy <https://cran.r-project.org/web/packages/policies.
 
 We need to check the number of CPUs used in examples. Export ``_R_CHECK_EXAMPLE_TIMING_CPU_TO_ELAPSED_THRESHOLD_=2.5`` before running ``R CMD check --as-cran`` `[1] <#references>`__ and make sure the machine you are using has enough CPU cores to reveal any potential policy violation.
 
+Read The Docs
+-------------
+
+We might need to manually activate the new release branch for `read the docs
+<https://xgboost.readthedocs.io/>`__ and set it as the default branch in the console `[2]
+<#references>`__. Please check the document build and make sure the correct branch is
+activated and selected after making a new release.
+
 References
 ----------
 
 [1] https://stat.ethz.ch/pipermail/r-package-devel/2022q4/008610.html
+
+[2] https://github.com/readthedocs/readthedocs.org/issues/12073