[Setup] Can switch to use the latest sark

sark was pinpointed to 2.0 when moved to Python3. As sark is now
more developed, we can use the latest version withouta Python issues.
Solves one of the cases in issue CheckPointSW#41.

setup.py

@@ -16,7 +16,7 @@
       url='https://github.com/CheckPointSW/Karta',
       license='MIT',
       packages=find_packages(),
-      install_requires=['elementals', 'sark==2.0', 'pydocstyle', 'flake8', 'click', 'scikit-learn'],
+      install_requires=['elementals', 'sark', 'pydocstyle', 'flake8', 'click', 'scikit-learn'],
       classifiers=[
                     "Programming Language :: Python :: 3",
                     "License :: OSI Approved :: MIT License (MIT License)",