Add release notes page for version 0.12.0

Patrole 0.12.0 has been released [1].
This commit adds a new page for 0.12.0 release notes.

[1] https://review.opendev.org/c/openstack/releases/+/783115

Change-Id: Ibbb1000d633372e2ca37b306fec3c284059905ba
diff --git a/releasenotes/source/index.rst b/releasenotes/source/index.rst
index 4479be0..9ef771a 100644
--- a/releasenotes/source/index.rst
+++ b/releasenotes/source/index.rst
@@ -6,6 +6,7 @@
    :maxdepth: 1
 
    unreleased
+   v0.12.0
    v0.11.0
    v0.10.0
    v0.9.0
diff --git a/releasenotes/source/v0.12.0.rst b/releasenotes/source/v0.12.0.rst
new file mode 100644
index 0000000..538e1f3
--- /dev/null
+++ b/releasenotes/source/v0.12.0.rst
@@ -0,0 +1,6 @@
+=====================
+v0.12.0 Release Notes
+=====================
+
+.. release-notes:: 0.12.0 Release Notes
+   :version: 0.12.0