Make requirements installable

docs/requirements.in

@@ -5,7 +5,7 @@
 # Please add developer dependencies which are not needed to install
 # Stackspin to requirements-dev.txt!
 #
+recommonmark
 sphinx
 sphinx-design
 sphinx-rtd-theme
-recommonmark

docs/requirements.txt

@@ -14,7 +14,7 @@ charset-normalizer==2.0.9
     # via requests
 commonmark==0.9.1
     # via recommonmark
-docutils==0.18.1
+docutils==0.17.1
     # via
     #   recommonmark
     #   sphinx
@@ -30,8 +30,10 @@ markupsafe==2.0.1
 packaging==21.3
     # via sphinx
 pygments==2.10.0
-    # via sphinx
-pyparsing==2.4.7
+    # via
+    #   -r requirements.in
+    #   sphinx
+pyparsing==3.0.6
     # via packaging
 pytz==2021.3
     # via babel