Update version of Estimator.

Also...
- Use capture group in sed command so we only need to update
  version in setup.py
- Add hour to nightly version string so we can, if need be, release
  multiple nightlies a day.

PiperOrigin-RevId: 225910161

tensorflow_estimator/tools/pip_package/setup.py

@@ -30,7 +30,7 @@
 # This version string is semver compatible, but incompatible with pip.
 # For pip, we will remove all '-' characters from this string, and use the
 # result for pip.
-_VERSION = '1.11.0'
+_VERSION = '1.13.0'
 
 REQUIRED_PACKAGES = [
     'absl-py >= 0.1.6',