pin sphinx components/deps for compatibility with existing sphinx ver…

…sion

setup.cfg

@@ -47,6 +47,8 @@ python_requires = >= 3.9
 
 [options.extras_require]
 dev =
+# later versions of alabaster require sphinx>=3.4
+    alabaster <=0.7.13
     black~=23.7.0
     flake8~=6.1.0
     flake8-bugbear~=23.7.10
@@ -62,6 +64,15 @@ dev =
     pre-commit~=3.3.3
     sphinx~=3.2.1
     sphinx-rtd-theme~=0.5.0
+
+# unclear why the following pins are necessary, but without them, versions dependent on sphinx>=5.0 are installed
+    sphinxcontrib-applehelp==1.0.4
+    sphinxcontrib-devhelp==1.0.2
+    sphinxcontrib-htmlhelp==2.0.1
+    sphinxcontrib-jsmath==1.0.1
+    sphinxcontrib-qthelp==1.0.3
+    sphinxcontrib-serializinghtml==1.1.5
+
     tox~=4.11.0
     types-psutil~=5.9.5
     types_requests~=2.28