Update tag links in README
Team and repository tags
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-.. image:: https://governance.openstack.org/badges/tacker.svg
- :target: https://governance.openstack.org/reference/tags/index.html
+.. image:: https://governance.openstack.org/tc/badges/tacker.svg
+ :target: https://governance.openstack.org/tc/reference/tags/index.html
.. Change things from this point on
