Add back version numbers in docs/requirements.in

docs/requirements.in

@@ -5,8 +5,8 @@
 # Please add developer dependencies which are not needed to install
 # Stackspin to requirements-dev.txt!
 #
-recommonmark
-sphinx
-sphinx-design
-sphinx-rtd-theme
-sphinx-version-warning
+recommonmark==0.7.1
+sphinx==4.4.0
+sphinx-design==0.0.13
+sphinx-rtd-theme==1.0.0
+sphinx-version-warning==1.1.2