Update docs requirements.

Author: Julian

docs/requirements.txt

@@ -16,8 +16,14 @@ certifi==2022.12.7
     # via requests
 charset-normalizer==3.0.1
     # via requests
+contourpy==1.0.7
+    # via matplotlib
+cycler==0.11.0
+    # via matplotlib
 docutils==0.19
     # via sphinx
+fonttools==4.38.0
+    # via matplotlib
 furo==2022.12.7
     # via -r docs/requirements.in
 idna==3.4
@@ -30,12 +36,24 @@ jinja2==3.1.2
     # via sphinx
 file:.#egg=jsonschema_specifications
     # via -r docs/requirements.in
+kiwisolver==1.4.4
+    # via matplotlib
 markupsafe==2.1.2
     # via jinja2
+matplotlib==3.6.3
+    # via sphinxext-opengraph
 multidict==6.0.4
     # via yarl
+numpy==1.24.2
+    # via
+    #   contourpy
+    #   matplotlib
 packaging==23.0
-    # via sphinx
+    # via
+    #   matplotlib
+    #   sphinx
+pillow==9.4.0
+    # via matplotlib
 pyenchant==3.2.2
     # via sphinxcontrib-spelling
 pygments==2.14.0
@@ -45,14 +63,20 @@ pygments==2.14.0
     #   sphinx
 pygments-github-lexers==0.0.5
     # via -r docs/requirements.in
+pyparsing==3.0.9
+    # via matplotlib
 pyrsistent==0.19.3
     # via referencing
+python-dateutil==2.8.2
+    # via matplotlib
 pytz==2022.7.1
     # via babel
-referencing==0.9.2
+referencing==0.14.0
     # via jsonschema-specifications
 requests==2.28.2
     # via sphinx
+six==1.16.0
+    # via python-dateutil
 snowballstemmer==2.2.0
     # via sphinx
 soupsieve==2.3.2.post1
@@ -83,7 +107,7 @@ sphinxcontrib-serializinghtml==1.1.5
     # via sphinx
 sphinxcontrib-spelling==7.7.0
     # via -r docs/requirements.in
-sphinxext-opengraph==0.7.5
+sphinxext-opengraph==0.8.0
     # via -r docs/requirements.in
 urllib3==1.26.14
     # via requests