adds service-types-authority repo to TC

This is like the api-wg, but a dedicated repository for doing the
service types authority.

Depends-On: I75f7066dca7b26204fa7a0196fd019c1b33aa3a3

Change-Id: I1a28446fc3279b69f05f8089d30b05b6e8d14801

reference/technical-committee-repos.yaml

@@ -4,4 +4,5 @@ Technical Committee:
   - repo: openstack/openstack-specs
   - repo: openstack/api-wg
   - repo: openstack/project-team-guide
+  - repo: openstack/service-types-authority
   - repo: openstack/election