Add urllib3 dependency to requirements.txt, setup.py and README

README.md

@@ -40,6 +40,7 @@ PyI40AAS requires the following Python packages to be installed for production u
 `setup.py` to be fetched automatically when installing with `pip`:
 * `python-dateutil` (BSD 3-clause License)
 * `lxml` (BSD 3-clause License, using `libxml2` under MIT License)
+* `urllib3` (MIT License)
 * `pyecma376-2` (Apache License v2.0)
 
 Optional production usage dependencies:

requirements.txt

@@ -3,3 +3,4 @@ lxml>=4.2,<5
 python-dateutil>=2.8,<3.0
 pyecma376-2>=0.2.4
 psutil>=5.6
+urllib3>=1.26<2.0

setup.py

@@ -47,6 +47,7 @@ setuptools.setup(
     install_requires=[
         'python-dateutil>=2.8,<3',
         'lxml>=4.2,<5',
+        'urllib3>=1.26<2.0',
         'pyecma376-2>=0.2.4',
     ]
 )