Prepare for relase using OpenStack release process

xstatic-spin has never been released using the OpenStack release
prociess with openstack/releases repository. To sync the release
history in openstack/releases and PyPI, we need to release a new
version, so the xstatic version is bumped.

README is also updated to match the length of the title marker
to the length of the title.

Change-Id: I27f5846730d2073bb39641b751461f410dab0a3c

README.txt

@@ -1,5 +1,5 @@
 XStatic-Spin
---------------
+------------
 
 Spin JavaScript library packaged for setuptools (easy_install) / pip.
 

xstatic/pkg/spin/__init__.py

@@ -13,7 +13,7 @@ NAME = __name__.split('.')[-1] # package name (e.g. 'foo' or 'foo_bar')
 
 VERSION = '1.2.5' # version of the packaged files, please use the upstream
                   # version number
-BUILD = '2' # our package build number, so we can release new builds
+BUILD = '3' # our package build number, so we can release new builds
              # with fixes for xstatic stuff.
 PACKAGE_VERSION = VERSION + '.' + BUILD # version used for PyPi