Merge pull request #132 from NASA-PDS/sphinx-deps-fix

 - pin sphinx components/deps for compatibility with sphinx 3.2.1

setup.cfg

@@ -29,14 +29,22 @@ package_dir =
 # by GitHub Actions to save time on spinning up the Roundup's container.
 
 install_requires =
+    alabaster <=0.7.13
     github3.py==1.3.0
-    requests==2.23.0
+    lxml==4.6.3
     packaging==21.0
+    requests==2.23.0
+    sphinx-rtd-theme~=0.5.0
+    sphinx-substitution-extensions==2020.9.30.0
     sphinx==3.2.1
+    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
     twine==3.4.2
     wheel==0.40.0
-    lxml==4.6.3
-    sphinx-substitution-extensions==2020.9.30.0
 
 
 [options.package_data]