Add readthedocs.org suppport files

Add .readthedocs.yaml, shield and docs/requirements.txt

.readthedocs.yaml

@@ -0,0 +1,16 @@
+# Read the Docs configuration file for Sphinx projects
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+version: 2
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+sphinx:
+  configuration: docs/conf.py
+  fail_on_warning: true
+formats:
+   - pdf
+   - epub
+python:
+   install:
+     - requirements: docs/requirements.txt

README.md

@@ -1,4 +1,5 @@
 [![CI](https://github.com/lpenz/disk-img-tool/actions/workflows/ci.yml/badge.svg)](https://github.com/lpenz/disk-img-tool/actions/workflows/ci.yml)
+[![docs](https://readthedocs.org/projects/disk-img-tool/badge/?version=stable)](https://disk-img-tool.readthedocs.io/en/stable/?badge=stable)
 [![coveralls](https://coveralls.io/repos/github/lpenz/disk-img-tool/badge.svg?branch=main)](https://coveralls.io/github/lpenz/disk-img-tool?branch=main)
 [![PyPI](https://img.shields.io/pypi/v/disk-img-tool)](https://pypi.org/project/disk-img-tool/)
 [![github](https://img.shields.io/github/v/release/lpenz/disk-img-tool?logo=github)](https://github.com/lpenz/disk-img-tool/releases)

docs/requirements.txt

@@ -0,0 +1 @@
+myst-parser