Update master for stable/2023.1

Add file to the reno documentation build to show release notes for
stable/2023.1.

Use pbr instruction to increment the minor version number
automatically so that master versions are higher than the versions on
stable/2023.1.

Sem-Ver: feature
Change-Id: I80f227a59c36693c83bb94890536745610ba2393

releasenotes/source/2023.1.rst

@@ -0,0 +1,6 @@
+===========================
+2023.1 Series Release Notes
+===========================
+
+.. release-notes::
+   :branch: stable/2023.1

releasenotes/source/index.rst

@@ -6,6 +6,7 @@
    :maxdepth: 1
 
    unreleased
+   2023.1
    zed
    yoga
    xena