requirements update

Author: Zebin Yang

requirements.txt

@@ -3,5 +3,5 @@
 ### $ pip install -r requirements.txt   
 
 numpy>=1.15.2
-sklearn
-matplotlib>=2.2.2
+scikit-learn>=0.23.0
+matplotlib>=3.1.3

setup.py

@@ -8,6 +8,5 @@
       author_email='[email protected]',
       license='GPL',
       packages=['simtree'],
-      install_requires=[
-          'matplotlib', 'numpy', 'sklearn'],
+      install_requires=['matplotlib>=3.1.3', 'numpy>=1.15.2', 'scikit-learn>=0.23.0', 'rpy2'],
       zip_safe=False)