Bump version to 0.5.0 and update Ray Tune lower bound to 2.7.1 (#281)

Author: justinvyu

setup.py

@@ -8,7 +8,7 @@
 # depends on Ray, then we create a cyclic dep.
 # workaround from: https://stackoverflow.com/a/17626524
 with open("tune_sklearn/_version.py") as f:
-    text = f.readlines()  # Returns ['__version__ = "0.4.6"']
+    text = f.readlines()  # Returns ['__version__ = "x.x.x"']
     __version__ = text[-1].split()[-1].strip("\"'")
 
 VERSION = os.environ.get("TSK_RELEASE_VERSION", __version__)
@@ -28,6 +28,6 @@
     long_description_content_type="text/markdown",
     url="https://github.com/ray-project/tune-sklearn",
     install_requires=[
-        "scikit-learn", "scipy", "ray[tune]>=2.0.0", "numpy>=1.16"
+        "scikit-learn", "scipy", "ray[tune]>=2.7.1", "numpy>=1.16"
     ],
 )

tune_sklearn/_version.py

@@ -1 +1 @@
-__version__ = "0.4.6"
+__version__ = "0.5.0"