docs: update readthedocs config

.readthedocs.yaml

@@ -0,0 +1,19 @@
+# Configuration on how ReadTheDocs (RTD) builds our documentation
+# ref: https://readthedocs.org/projects/repo2docker-service/
+# ref: https://docs.readthedocs.io/en/stable/config-file/v2.html
+#
+version: 2
+
+sphinx:
+  configuration: docs/source/conf.py
+
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.10"
+
+python:
+  install:
+    - requirements: docs/requirements.txt
+    - method: pip
+      path: .

docs/source/conf.py

@@ -3,7 +3,11 @@
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = ["sphinx.ext.extlinks", "sphinxcontrib.autoprogram", "myst_parser"]
+extensions = [
+    "myst_parser",
+    "sphinx.ext.extlinks",
+    "sphinxcontrib.autoprogram",
+]
 
 extlinks = {
     "issue": ("https://github.com/jupyterhub/repo2docker/issues/%s", "Issue #"),

docs/source/contributing/contributing.md

@@ -187,6 +187,7 @@ Then you are good to go!
 You can build and inspect the result of documentation changes locally.
 
 ```bash
+pip install -e .
 pip install -r docs/requirements.txt
 
 cd docs/

readthedocs.yml

@@ -1,6 +0,0 @@
-name: repo2docker
-type: sphinx
-python:
-  version: 3
-  setup_py_install: true
-requirements_file: docs/requirements.txt