Fix readthedocs build (#495)

* Update rtd build environment

* Clean up path

* Add pandoc version restrictions for nbconvert

* Remove pandoc version requirements since pypi has wrong package

* Constrain nbconvert version on rtd

.readthedocs.yaml

@@ -12,9 +12,9 @@ submodules:
 
 # Set the version of Python and other tools you might need
 build:
-  os: ubuntu-20.04
+  os: ubuntu-22.04
   tools:
-    python: "3.8"
+    python: "3.10"
   apt_packages:
     - graphviz
     - libopenblas-dev
@@ -29,3 +29,4 @@ sphinx:
 python:
    install:
    - requirements: docs/docs_requirements.txt
+   - requirements: docs/rtd_requirements.txt

docs/rtd_requirements.txt

@@ -0,0 +1,3 @@
+# nbconvert>=7.5 requires a version of pandoc that is not available
+#   in the readthedocs build environment
+nbconvert<7.5

docs/source/conf.py

@@ -5,7 +5,7 @@
 
 confpath = os.path.dirname(__file__)
 sys.path.append(confpath)
-rootpath = os.path.join(confpath, "..", "..")
+rootpath = os.path.realpath(os.path.join(confpath, "..", ".."))
 sys.path.append(rootpath)
 
 from docsutil import insert_inheritance_diagram, package_classes, run_conf_files