Twitter-oss: Prepare OSS util for release 19.8.1

Problem

We want to release the next versions of our Twitter OSS util 19.8.1

Solution

Prepare util for their next releases.

Result

We will need to temporarily upgrade all versions for passing build.
But we will only publish util 19.8.1.
post-release will reset all versions back to 19.9.0-SNAPSHOT.

JIRA Issues: CSL-8688

Differential Revision: https://phabricator.twitter.biz/D356166

CHANGELOG.rst

@@ -7,6 +7,9 @@ Note that ``PHAB_ID=#`` and ``RB_ID=#`` correspond to associated messages in com
 Unreleased
 ----------
 
+19.8.1
+------
+
 New Features
 ~~~~~~~~~~~~
 

README.md

@@ -1,6 +1,6 @@
 # Twitter Util
 
-[![Build status](https://travis-ci.org/twitter/util.svg?branch=develop)](https://travis-ci.org/twitter/util)
+[![Build status](https://travis-ci.org/twitter/util.svg?branch=master)](https://travis-ci.org/twitter/util)
 [![Codecov](https://codecov.io/gh/twitter/util/branch/develop/graph/badge.svg)](https://codecov.io/gh/twitter/util)
 [![Project status](https://img.shields.io/badge/status-active-brightgreen.svg)](#status)
 [![Gitter](https://badges.gitter.im/twitter/finagle.svg)](https://gitter.im/twitter/finagle?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
@@ -35,7 +35,7 @@ for more details about how to contribute.
 An example SBT dependency string for the `util-collection` tools would look like this:
 
 ```scala
-val collUtils = "com.twitter" %% "util-collection" % "19.8.0"
+val collUtils = "com.twitter" %% "util-collection" % "19.8.1"
 ```
 
 # Units

build.sbt

@@ -1,7 +1,7 @@
 import scoverage.ScoverageKeys
 
 // All Twitter library releases are date versioned as YY.MM.patch
-val releaseVersion = "19.9.0-SNAPSHOT"
+val releaseVersion = "19.8.1"
 
 val zkVersion = "3.5.0-alpha"
 val zkClientVersion = "0.0.81"