Fix ReadTheDocs config for Poetry (#1663)

.readthedocs.yaml

@@ -3,10 +3,16 @@ version: 2
 sphinx:
   configuration: docs/conf.py
 
-python:
-  version: 3.7
-  install:
-    - method: pip
-      path: .
-      extra_requirements:
-        - docs
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "3.8"
+  jobs:
+    post_create_environment:
+      # Install poetry
+      - pip install poetry
+      # Tell poetry to not use a virtual environment
+      - poetry config virtualenvs.create false
+    post_install:
+      # Install dependencies with 'docs' dependency group
+      - poetry install --with docs

docs/conf.py

@@ -62,12 +62,12 @@ copyright = '2018, Zalando SE'
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
-import connexion
+from importlib.metadata import version
 
-# The short X.Y version.
-version = connexion.__version__.rsplit('.', 1)[0]
 # The full version, including alpha/beta/rc tags.
-release = connexion.__version__
+release = version('connexion')
+# The short X.Y version.
+version = release.rsplit('.', 1)[0]
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.