Upload tripleo-heat-templates releases to PyPi

We must have forgotten to configure infra to upload releases of t-h-t to PyPi.
While t-h-t repo mainly consists of Heat templates, it also contains merge.py
script we are using.

Change-Id: I454476a0802928595b7ecb8577dfd67d19987b34
Merge "Upload tripleo-heat-templates releases to PyPi"