build: fix readthedocs build error

docs/requirements.txt

@@ -1 +1,39 @@
-sphinx-js>=2.8
+# This file was produced by running pip freeze after installing
+# the following in venv:
+# sphinx-js>=2.8
+# Sphinx==3.5.4
+# Pin Jinja2 and markupsafe versions
+# https://github.com/mozilla/sphinx-js/issues/190
+# markupsafe==2.0.1
+# Jinja2>2.0,<3.0
+# sphinx_rtd_theme
+
+Babel==2.10.3
+certifi==2022.9.24
+charset-normalizer==2.1.1
+docutils==0.16
+idna==3.4
+imagesize==1.4.1
+# Pin Jinja2 and markupsafe versions
+# https://github.com/mozilla/sphinx-js/issues/190
+Jinja2==2.11.3
+MarkupSafe==2.0.1
+packaging==21.3
+parsimonious==0.7.0
+Pygments==2.13.0
+pyparsing==3.0.9
+pytz==2022.5
+requests==2.28.1
+six==1.16.0
+snowballstemmer==2.2.0
+# Use same sphinx version required by sphinx-js 3.1.2
+Sphinx==3.5.4
+sphinx-js==3.1.2
+sphinx-rtd-theme==1.0.0
+sphinxcontrib-applehelp==1.0.2
+sphinxcontrib-devhelp==1.0.2
+sphinxcontrib-htmlhelp==2.0.0
+sphinxcontrib-jsmath==1.0.1
+sphinxcontrib-qthelp==1.0.3
+sphinxcontrib-serializinghtml==1.1.5
+urllib3==1.26.12