Add constraint to Python 3.5 dependency

requirements/constraints.txt

@@ -15,3 +15,6 @@ Django<2.3.0
 
 # mock version 4.0.0 drops support for python 3.5
 mock<4.0.0
+
+# Zip > 1.2.0 drops support for python 3.5
+zipp<1.2.0
\ No newline at end of file

requirements/tox.txt

@@ -15,6 +15,6 @@ py==1.8.1                 # via tox
 pyparsing==2.4.7          # via packaging
 six==1.15.0               # via packaging, tox, virtualenv
 toml==0.10.1              # via tox
-tox==3.15.2               # via -r requirements/tox.in
-virtualenv==20.0.21       # via tox
-zipp==1.2.0               # via importlib-metadata, importlib-resources
+tox==3.15.0               # via -r requirements/tox.in
+virtualenv==20.0.20       # via tox
+zipp==1.1.1               # via -c requirements/constraints.txt, importlib-metadata

requirements/travis.txt

@@ -72,7 +72,7 @@ webob==1.8.6              # via -r requirements/test.txt, xblock
 wrapt==1.11.2             # via -r requirements/test.txt, astroid
 xblock-utils==2.1.1       # via -r requirements/test.txt
 xblock==1.3.1             # via -r requirements/test.txt, xblock-utils
-zipp==3.1.0               # via -r requirements/tox.txt, importlib-metadata
+zipp==1.1.1               # via -c requirements/constraints.txt, -r requirements/tox.txt, importlib-metadata
 
 # The following packages are considered to be unsafe in a requirements file:
 # setuptools