readthedocs: add configuration file

Readthedocs is attempting to use our /requirements.txt file as a Python
requirements file, which it is not. Add a Readthedocs configuration file
to tell it to not use any requirements file.

diff --git a/.readthedocs.yaml b/.readthedocs.yaml
new file mode 100644 (file)
index 0000000..bc23deb
--- /dev/null
+++ b/.readthedocs.yaml
@@ -0,0 +1,9 @@
+# Required by Read The Docs
+version: 2
+
+python:
+  version: "3.8"
+
+  # Use an empty install section to avoid RTD from picking up a non-python
+  # requirements.txt file.
+  install: []