Add 26.1.0 releasenote page

Add a new releasenote page for the latest 26.1.0 release
so that the releasenotes written within that release are
grouped together and showed properly.

Change-Id: I14c6743ce0d14d9265be5ee12d33f4955d0d8ada
diff --git a/releasenotes/source/v26.1.0.rst b/releasenotes/source/v26.1.0.rst
new file mode 100644
index 0000000..554cf1f
--- /dev/null
+++ b/releasenotes/source/v26.1.0.rst
@@ -0,0 +1,5 @@
+=====================
+v26.1.0 Release Notes
+=====================
+.. release-notes:: 26.1.0 Release Notes
+   :version: 26.1.0