Add docs requirements to pyproject.toml (#1494)

* Add `docs` requirements to `pyproject.toml`

* Add release note

* Exclude `numpy` version `1.21.0`

Move the RTD exclusion to the `numpy` dependency directly.

* Require `numcodecs[msgpack]` for `docs`

* Update references for installing doc dependencies

Author: jakirkham

Diff for: .pyup.yml

@@ -13,6 +13,3 @@ requirements:
   - requirements_dev_optional.txt:
       pin: True
       update: all
-  - requirements_rtfd.txt:
-      pin: False
-      update: False

Diff for: .readthedocs.yaml

@@ -10,6 +10,7 @@ sphinx:
 
 python:
   install:
-    - requirements: requirements_rtfd.txt
     - method: pip
       path: .
+      extra_requirements:
+        - docs

Diff for: docs/contributing.rst

@@ -92,8 +92,8 @@ the repository, you can do something like the following::
     $ mkdir -p ~/pyenv/zarr-dev
     $ python -m venv ~/pyenv/zarr-dev
     $ source ~/pyenv/zarr-dev/bin/activate
-    $ pip install -r requirements_dev_minimal.txt -r requirements_dev_numpy.txt -r requirements_rtfd.txt
-    $ pip install -e .
+    $ pip install -r requirements_dev_minimal.txt -r requirements_dev_numpy.txt
+    $ pip install -e .[docs]
 
 To verify that your development environment is working, you can run the unit tests::
 

Diff for: docs/release.rst

@@ -24,6 +24,9 @@ Maintenance
 * Require ``setuptools_scm`` version ``1.5.4``\+
   By :user:`John A. Kirkham <jakirkham>` :issue:`1477`.
 
+* Add ``docs`` requirements to ``pyproject.toml``
+  By :user:`John A. Kirkham <jakirkham>` :issue:`1494`.
+
 .. _release_2.16.0:
 
 2.16.0

Diff for: pyproject.toml

@@ -13,7 +13,7 @@ maintainers = [
 requires-python = ">=3.8"
 dependencies = [
     'asciitree',
-    'numpy>=1.20',
+    'numpy>=1.20,!=1.21.0',
     'fasteners',
     'numcodecs>=0.10.0',
 ]
@@ -43,6 +43,16 @@ jupyter = [
     'ipytree>=0.2.2',
     'ipywidgets>=8.0.0',
 ]
+docs = [
+    'sphinx',
+    'sphinx_design',
+    'sphinx-issues',
+    'sphinx-copybutton',
+    'sphinx-rtd-theme',
+    'pydata-sphinx-theme',
+    'numpydoc',
+    'numcodecs[msgpack]',
+]
 
 [project.urls]
 "Bug Tracker" = "https://github.com/zarr-developers/zarr-python/issues"