train: release osc-placement 1.7.0

Minor version bump since there are new features.

$ git log --no-merges --oneline --no-decorate 1.6.0..origin/master
8bbca01 Follow up for Ib0cbb58d0adbbcfe83ee48d2ff6c9af1a516a7ae
5cf7d77 Add --dry-run option to 'resource provider inventory set'
0ce562f Add --amend option to 'resource provider inventory set'
f08cb39 Add --aggregate option to 'resource provider inventory set'
51c0064 Cap sphinx for py2 to match global requirements

Change-Id: Ic0de7b7a05fefc930d507d150689dfe3cf07c598

deliverables/train/osc-placement.yaml

@@ -11,3 +11,7 @@ releases:
     projects:
       - repo: openstack/osc-placement
         hash: bb001133b277e85afba1827f75927ec6d04df683
+  - version: 1.7.0
+    projects:
+      - repo: openstack/osc-placement
+        hash: 8bbca01dbddb1eb374d708553ccaddb4f130116e