Update requirements to match current salt

Updates requirements to match current salt requirements for zeromq
and tornado.

tests/requirements.txt

@@ -3,8 +3,9 @@ pytest>=3.5.0,<4.0.0
 pytest-rerunfailures
 pytest-cov
 git+https://github.com/vmware-archive/pytest-salt@master#egg=pytest-salt
-tornado<5.0.0
+tornado==6.1
 CherryPy
 setuptools_scm
-pyzmq>=2.2.0,<17.1.0; python_version == '3.4'  # pyzmq 17.1.0 stopped building wheels for python3.4
-pyzmq>=2.2.0; python_version != '3.4'
+pyzmq<=20.0.0 ; python_version < "3.6"
+pyzmq>=17.0.0 ; python_version < "3.9"
+pyzmq>19.0.2 ; python_version >= "3.9"