Update .readthedocs.yml (#394)

* Update .readthedocs.yml

* Delete requirements.txt

Author: sobolevn

.readthedocs.yml

@@ -1,10 +1,20 @@
+# .readthedocs.yaml
 version: 2
 
-python:
-  version: 3.8
-  install:
-    - requirements: docs/requirements.txt
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-20.04
+  tools: {python: "3.9"}
+  jobs:
+    pre_create_environment:
+      - asdf plugin add poetry
+      - asdf install poetry latest
+      - asdf global poetry latest
+      - poetry config virtualenvs.create false
+    post_install:
+      - poetry install
 
+# Build documentation in the docs/ directory with Sphinx
 sphinx:
   configuration: docs/conf.py
   fail_on_warning: true