Removed package/meta.yml (#1540)

* Unpinned iris and removed meta.yml

* Reverted unopinning of iris

* Updated release instructions

* Apply suggestions from code review

Co-authored-by: Bouwe Andela <b.andela@esciencecenter.nl>

Co-authored-by: Bouwe Andela <b.andela@esciencecenter.nl>

Author: schlunma

doc/contributing.rst

@@ -642,9 +642,6 @@ the following files:
   consuming.)
 - ``setup.py``
   contains all Python dependencies, regardless of their installation source
-- ``package/meta.yaml``
-  contains dependencies for the conda package; all Python and compiled
-  dependencies that can be installed from conda should be listed here
 
 Note that packages may have a different name on
 `conda-forge <https://conda-forge.org/>`__ than on PyPI_.
@@ -740,8 +737,8 @@ to run their favourite recipe using this branch.
 3. Increase the version number
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-The version number is stored in ``esmvalcore/_version.py``,
-``package/meta.yaml``, ``CITATION.cff``. Make sure to update all files.
+The version number is stored in ``esmvalcore/_version.py``, ``CITATION.cff``.
+Make sure to update both files.
 Also update the release date in ``CITATION.cff``.
 See https://semver.org for more information on choosing a version number.
 Make a pull request and get it merged into ``main`` and cherry pick it into
@@ -779,39 +776,7 @@ Then click the
 `releases tab <https://github.com/ESMValGroup/ESMValCore/releases>`__
 and create the new release from the release branch (i.e. not from ``main``).
 
-7. Create and upload the Conda package
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The package is automatically uploaded to the
-`ESMValGroup conda channel <https://anaconda.org/esmvalgroup/esmvalcore>`__
-by a GitHub action (note that this is an obsolete procedure for the main package upload,
-since the main package is now uploaded to
-`conda-forge conda channel <https://anaconda.org/conda-forge>`__ via
-the upload to PyPi, but we still upload to the esmvalgroup channel as a backup option;
-also the upload to esmvalcore gives us a chance to verify it immediately after upload).
-If this has failed for some reason, build and upload the package manually by
-following the instructions below.
-
-Follow these steps to create a new conda package:
-
--  Check out the tag corresponding to the release,
-   e.g. ``git checkout tags/v2.1.0``
--  Make sure your current working directory is clean by checking the output
-   of ``git status`` and by running ``git clean -xdf`` to remove any files
-   ignored by git.
--  Edit ``package/meta.yaml`` and uncomment the lines starting with ``git_rev`` and
-   ``git_url``, remove the line starting with ``path`` in the ``source``
-   section.
--  Activate the base environment ``conda activate base``
--  Install the required packages:
-   ``conda install -y conda-build conda-verify ripgrep anaconda-client``
--  Run ``conda build package -c conda-forge`` to build the
-   conda package
--  If the build was successful, upload the package to the esmvalgroup
-   conda channel, e.g.
-   ``anaconda upload --user esmvalgroup /path/to/conda/conda-bld/noarch/esmvalcore-2.3.1-py_0.tar.bz2``.
-
-8. Create and upload the PyPI package
+7. Create and upload the PyPI package
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The package is automatically uploaded to the
@@ -842,6 +807,34 @@ Follow these steps to create a new Python package:
 You can read more about this in
 `Packaging Python Projects <https://packaging.python.org/tutorials/packaging-projects/>`__.
 
+8. Create the Conda package
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The ``esmvalcore`` package is published on the `conda-forge conda channel
+<https://anaconda.org/conda-forge>`__.
+This is done via a pull request on the `esmvalcore-feedstock repository
+<https://github.com/conda-forge/esmvalcore-feedstock>`__.
+
+For the final release, this pull request is automatically opened by a bot.
+An example pull request can be found `here
+<https://github.com/conda-forge/esmvalcore-feedstock/pull/11>`__.
+Follow the instructions by the bot to finalize the pull request.
+This step mostly contains updating dependencies that have been changed during
+the last release cycle.
+Once approved by the `feedstock maintainers
+<https://github.com/conda-forge/esmvalcore-feedstock/blob/main/README.md#feedstock-maintainers>`__
+they will merge the pull request, which will in turn publish the package on
+conda-forge some time later.
+Contact the feedstock maintainers if you want to become a maintainer yourself.
+
+To publish a release candidate, you have to open a pull request yourself.
+An example for this can be found `here
+<https://github.com/conda-forge/esmvalcore-feedstock/pull/35>`__.
+Make sure to use the `rc branch
+<https://github.com/conda-forge/esmvalcore-feedstock/tree/rc>`__ as the target
+branch for your pull request and follow all instructions given by the linter
+bot.
+
 
 .. _`@ESMValGroup/esmvaltool-coreteam`: https://github.com/orgs/ESMValGroup/teams/esmvaltool-coreteam
 .. _`@ESMValGroup/esmvaltool-developmentteam`: https://github.com/orgs/ESMValGroup/teams/esmvaltool-developmentteam