Fix readthedocs build

Author: pganssle

.github/workflows/tests.yml

@@ -16,9 +16,13 @@ jobs:
             os: "windows-latest"
           - python-version: "2.7"
             os: "macos-latest"
+          - python-version: "2.7"
+            os: "ubuntu-latest"
           - python-version: "3.6"
             os: "ubuntu-latest"
         include:
+          - python-version: "2.7"
+            os: "ubuntu-20.04"
           - python-version: "3.6"
             os: "ubuntu-20.04"
     env:

.readthedocs.yml

@@ -1,7 +1,15 @@
 version: 2 # Required in order to install with pip
 
+build:
+  os: "ubuntu-22.04"
+  tools:
+      python: "3.11"
+
+sphinx:
+  configuration: "docs/conf.py"
+
 python:
-  version: 3.7
   install:
-    - path: .
+    - method: "pip"
+      path: "."
     - requirements: docs/requirements.txt