update rtd config file format

.readthedocs.yaml

@@ -0,0 +1,13 @@
+version: 2
+
+build:
+  os: ubuntu-20.04
+  tools:
+    python: "3.7"
+
+sphinx:
+   configuration: docs/conf.py
+
+python:
+   install:
+   - requirements: requirements-rtd.txt

docker/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.6.8-slim as base
+FROM python:3.7.13-slim as base
 
 WORKDIR /work
 

docs/development.rst

@@ -23,7 +23,12 @@ Release process
 
 Hiku supports semver versioning.
 
-#. Update the version number in the `hiku/__init__.py`` file.
+#. Update the version number in the ``hiku/__init__.py`` file.
 #. Update the changelog in the `docs/changelog/changes_0X.rst` file.
 #. Merge changes into master.
-#. Create annotated tag. This will trigger a new release action on GitHub and publish new package to `pypi`.
+#. Run `lets release <version> -m 'your release message'`. This will create and push annotated tag. When new tag pushed, new release action on GitHub will publish new package to `pypi`.
+
+Documentation release
+~~~~~~~~~~~~~~~~~~~~~
+
+Documentation released on new commits in master.