Add Oslo feature freeze to Victoria schedule

Oslo freezes earlier than other projects in order to give its
consumers time to consume any new features that are added before
their feature freezes.[0]

This adds that date to the release calendar so it is easy to find.

Change-Id: I19938bc16629754001f811e4ffe54c555c0833dc
0: https://specs.openstack.org/openstack/oslo-specs/specs/policy/feature-freeze.html

doc/source/victoria/schedule.rst

@@ -188,3 +188,13 @@ Germany.
 Project-specific events
 =======================
 
+Oslo
+----
+
+.. _v-oslo-feature-freeze:
+
+Oslo Feature Freeze
+^^^^^^^^^^^^^^^^^^^
+
+All new Oslo features must be proposed and substantially complete, with unit
+tests by the end of the week.

doc/source/victoria/schedule.yaml

@@ -60,6 +60,8 @@ cycle:
 - end: '2020-08-28'
   name: R-7
   start: '2020-08-24'
+  project-specific:
+    - v-oslo-feature-freeze
 - end: '2020-09-04'
   name: R-6
   start: '2020-08-31'