correct short description in setup.py (#239)

Author: jbweston

setup.py

@@ -46,7 +46,7 @@ def get_version_and_cmdclass(package_name):
 
 setup(
     name="adaptive",
-    description="Adaptive parallel sampling of mathematical functions",
+    description="Parallel active learning of mathematical functions",
     version=version,
     python_requires=">=3.6",
     url="https://adaptive.readthedocs.io/",