Pin transitive dependencies

docs/requirements.in

@@ -0,0 +1 @@
+sphinx==7.0.0

docs/requirements.txt

@@ -1,9 +1,52 @@
-mock==1.0.1
-pillow==5.4.1
-alabaster>=0.7,<0.8,!=0.7.5
-commonmark==0.8.1
-recommonmark==0.5.0
-sphinx<2
-sphinx-rtd-theme<0.5
-readthedocs-sphinx-ext<2.2
-docutils>=0.14,<0.18
+#
+# This file is autogenerated by pip-compile with Python 3.9
+# by the following command:
+#
+#    pip-compile --output-file=requirements.txt --resolver=backtracking requirements.in
+#
+alabaster==0.7.13
+    # via sphinx
+babel==2.12.1
+    # via sphinx
+certifi==2023.5.7
+    # via requests
+charset-normalizer==3.1.0
+    # via requests
+docutils==0.19
+    # via sphinx
+idna==3.4
+    # via requests
+imagesize==1.4.1
+    # via sphinx
+importlib-metadata==6.6.0
+    # via sphinx
+jinja2==3.1.2
+    # via sphinx
+markupsafe==2.1.2
+    # via jinja2
+packaging==23.1
+    # via sphinx
+pygments==2.15.1
+    # via sphinx
+requests==2.30.0
+    # via sphinx
+snowballstemmer==2.2.0
+    # via sphinx
+sphinx==7.0.0
+    # via -r requirements.in
+sphinxcontrib-applehelp==1.0.4
+    # via sphinx
+sphinxcontrib-devhelp==1.0.2
+    # via sphinx
+sphinxcontrib-htmlhelp==2.0.1
+    # via sphinx
+sphinxcontrib-jsmath==1.0.1
+    # via sphinx
+sphinxcontrib-qthelp==1.0.3
+    # via sphinx
+sphinxcontrib-serializinghtml==1.1.5
+    # via sphinx
+urllib3==2.0.2
+    # via requests
+zipp==3.15.0
+    # via importlib-metadata